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You can use several words in query to find by all of them at the same time. In addition, if you are lucky search understands word forms and some synonyms. It supports search by title and author. Examples:
305— search for 305, most probably it will find blogs about the Round 305andrew stankevich contests— search for words "andrew", "stankevich" and "contests" at the same timeuser:mikemirzayanov title:testlib— search containing "testlib" in title by MikeMirzayanov"vk cup"— use quotes to find phrase as istitle:educational— search in title
Results
1.
launch
Last visit:
2 years ago
Registered:
9 years ago
2.
Codeforces celebrates its 15th anniversary! <img src="https://assets.codeforces.com/files/codeforces15.jpg" style="width:250px; float:right; margin: 0 1em 1em 1em;" />
Hi, Codeforces!
Around this time, 15 years ago, I was deploying the first version of Codeforces on a server, registering my account, and writing the first post. 15 years have passed. Well, happy anniversary to us!
For me, this is the most exciting adventure — full of ups and downs, hard work, and moments of joy. What's amazing is that it was never a lonely journey. I've always had caring and reliable friends by my side! That includes the Codeforces team, coordinators and problem writers, our partners in various events, all community members, and, of course, our sponsors — steadfast supporters and helpers.
Look at what we've accomplished together! Here are some of the key metrics over the years. There seems to be plenty to celebrate!
<center>
<img src="https://assets.codeforces.com/files/15/01-submissions.png" class="resource" style="width:300px;"/>...
3.
New: Diagnostics of Solutions in C++ <img src = "/predownloaded/b5/d2/b5d246ffc32dfe82c3cbac77d1898c5fcb62fa57.jpg" style = "float: right; margin: 0 1em 1em 1em;"/>
Hello!
I am pleased to report that two rounds of Codeforces have gone quite well in terms of the work of Codeforces, I am very glad about it. These <s>days</s> nights I spent in a profiler, fixing the code, researching the settings of MariaDB.
In addition, I managed to allocate several hours on Sunday (to be honest, until Monday morning) to finish the long-planned innovation.
Meet, diagnostics of solutions in C++!
Many Codeforces visitors are already tired of the questions of less experienced participants: "Why does my solution not work on some test on the Codeforces servers, if I locally launch it and it works correctly? You have the wrong compiler/servers!" In 99% of cases this is an example of <a href ="https://en.wikipedia.org/wiki/Undefined_behavior">undefined behavior</a> in a program. In other words, the program contains mistakes that, du...
does my solution not work on some test on the Codeforces servers, if I locally
launch it and it, drmemory). If an execution error occurs during this launch, the diagnostics
log will be displayed, on the Codeforces servers, if I locally launch it and it works correctly? You
have the wrong
4.
Polygon: AI-Powered Automatic Tips Hello, Codeforces!
<i>For the new members of the community, I would like to remind you that Polygon (https://polygon.codeforces.com/) is a system developed
and maintained by Codeforces for preparing programming problems. It is there that authors and coordinators develop all the problems for
the rounds. Moreover, I believe a significant (large?) portion of the problems for other competitions is also developed there: various
stages of ICPC, national competitions of different levels, educational problems for various courses, etc.
<b>In 2023, more than 50000 problems were prepared in Polygon (only those for which a package was compiled are counted)!</b></i>
Large language models are becoming an increasingly integral part of our lives, taking over routine and monotonous tasks.
With their help, problems created in Polygon will now have fewer typos and incorrect language constructions.
We have recently implemented three features in Polygon to ease routine tasks:
* Translati...
round started and took the time to manually launch the edit prompter. In most
(almost all?) problems, took the time to manually launch the edit prompter. In most (almost all?)
problems, it indeed suggested
5.
Competitive Programming Hall of Fame — cphof.org Hi Codeforces!
Today I'd like to introduce the new [Competitive Programming Hall of Fame](https://cphof.org) project that is available at [cphof.org](https://cphof.org)
#### Background
A long time ago I've noticed that there is no single source of information with the results of previously held large programming competitions. Moreover, plenty of older championships don't maintain their websites anymore, and it becomes hard or even impossible to find any details about them, which is pretty sad. So I've decided to create [Competitive Programming Hall of Fame](https://cphof.org).
#### About the project
Competitive Programming Hall Of Fame is a project created to preserve the history of international championships in competitive programming. This website collects the results of the final stages for both worldwide and regional contests. By international championship we mean a contest consisting ...
[user:tourist,2021-09-28] for some helpful pre-launch advice.
6.
Codeforces Global Rounds Hello!
It is always satisfying and important for me when former contest participants offer their help to the community and support the development of programming competitions. And now I am in a hurry to share the news that thanks to the support of <a href="https://www.xtxmarkets.com/">XTX Markets</a> and the personal participation of Yuri Bedny and Alexander Gerko, we are launching a new line of Codeforces Global Rounds. Hooray!
<img src="/predownloaded/2e/e2/2ee2f0f95f05aae6ca6f47812dae2dc2aabf277b.png" style="width:200px; float:right; margin: 0 1em 1em 1em"/>
Like many of you, I had never heard of <a href="https://www.xtxmarkets.com/">XTX Markets</a> before but it is one of the largest quantitative-driven electronic liquidity providers in the world. I understand little about the financial sector, but with their 34,148 cores and 42 petabytes of usable storage in their research cluster, XTX’s rapid growth and strong market share globally speak for themselves.
So, in 2019, w...
7.
Testlib: tests + CI Hello, Codeforces.
I have wanted for a long time and now, finally, I sat down and did it.
Many of you are familiar with my [Testlib](https://github.com/MikeMirzayanov/testlib) project. This is a library that helps you develop problems if you are using C++.
In the case of problems for Codeforces rounds, its use is mandatory. It seems to me that it is almost a de facto standard for preparing materials for completely different olympiads and competitions.
The history of С++-Testlib is almost lost in centuries, I published the first version in 2005.
Nowadays, making edits to Testlib has become tricky. The code grown to thousands of lines, also it has too long a history.
This increases the likelihood of accidentally changing some aspect of behavior, which will jeopardize the holding of a Codeforces round or another important competition.
In short, making a bug in this code or changing behavior anywhere is highly discouraged.
So I recently took the plunge and wrote some test...
. Tests are automatically run on any push or pull request. [cut] The launch is
carried out on, The launch is carried out on:
8.
Looking For EDU Lecturers <img src="/predownloaded/47/86/4786c2ec901c0b5b490794ca6fd5145f0dcdeae3.png" style="float:right; width: 400px; margin: 0 1em 1em 1em"/>
Hello!
I always like to think that Codeforces is not only a place where you come to compete but also a place where you can learn. Learn new things.
Two years ago, we launched the [EDU](https://codeforces.me/edu/courses) subproject, a platform for publishing classes. There are already several classes, but there are so many interesting topics around!
The Codeforces team can write the platform, make the technical foundation, but it would be great to write content with the support of the community.
Thanks to the support of competitive programming alumni, we have a budget for targeted grants for the preparation of new classes in the EDU section. Hope we have new content soon!
We are looking for lesson authors who could prepare and record one or more lessons. Those who are now red or have ever been red are invited.
We assume that one le...
9.
Help Egypt Fly to IOI 2025 **UPD: WE ARE FLYING TO THE IOI! Thanks to everyone who donated and all organizations that supported our journey!** We got support for our international flights from several organizations and the raised money through the crowdfunding will go towards funding our domestic flights and IOI registration.
Hello Codeforces,
I, along with [user:contee,2025-06-24], [user:is-this-dp,2025-06-24], and [user:3omar_ahmed,2025-06-24], am a member of Egypt's IOI 2025 team. For the past few years, the Ministry of Communications and Information Technology has supported the Egyptian IOI team to attend the competition. However, this year we are not receiving any institutional or government support.
We worked hard over the past year to get ready for the competition. The cost of attending the IOI for the Egyptian delegation, which includes our flight tickets, visa, and registration costs, is difficult for us to cover, especially given the current economic situation in Egypt. We have reached out to ...
10.
Refact.ai Match 1 (Codeforces Round 985, Div. 1 + Div. 2) Hello, Codeforces!
We (KDOI Team) are glad to invite you to take part in [contest:2029], which is the 8th CP contest held by us! You can view the previous rounds by us [here](/blog/entry/135847).
- Number of problems: $9$ ($0$ interactive);
- Start time: [contest_time:2029];
- Contest duration: $180$ minutes;
- Score distribution: $750-1250-1750-2250-2500-3000-3500-5000-5500$.
The problems were authored and prepared by [user:Error_Yuan,2024-11-05], [user:wyrqwq,2024-11-05], [user:Otomachi_Una,2024-11-05] and me [user:sszcdjr,2024-11-05].
---
<img src="/predownloaded/73/e1/73e1593107761ee6b925164110aa7307488b2215.png" style="float:right; margin: 0 0 2em 2em; width:300px;"/>
A few words from our sponsor:
We’re [Refact.ai](https://refact.ai/?utm_source=codeforces&utm_medium=post&utm_campaign=round_09112024&utm_content=cf_short_09112024), an open-source AI Coding Assistant, and on November 9th, we’ll be hosting our first round on Codeforces! Winners will receive ...
Refact.ai is pushing AI beyond simple code completion. Soon, we’ll launch the
Autonomous AI Agent—a
Announcement of Refact.ai Match 1 (Codeforces Round 985)
11.
I think we are checking the wrong thing against LLM cheating ### 1. What exactly is the problem
During rounds, a specific pattern has appeared: a participant gets ready-made code from an LLM and simply submits it, almost without understanding it.
This is not always caught by plagiarism: a person can rename variables, swap some parts of the code.
### 2. The idea
#### Xeppelin — an open-source tool, originally made for ICPC, which:
- is launched locally before the contest
- logs file changes in the working directory
- stores a development timeline (when and how the code changed)
- does not record the screen, keyboard, network, or tabs
- after the contest builds a visualization of activity
#### [This is not my tool, but you can find it here](https://github.com/KiK0S/xeppelin)
### 3. What exactly is proposed for Codeforces (implementation, not an idea)
The proposal is to use Xeppelin as an external source of behavioral data, without interfering with CF infrastructure.
Workflow:
1. The participant launches Xeppelin bef...
12.
Codeforces Round 955 (Div. 2, with prizes from NEAR!) Hello, Codeforces!
It's been a long journey, and I'm finally pleased to invite you to participate in our [contest:1982], which will take place on [contest_time:1982].
This round will be <b>rated</b> for all participants with a rating is <b>below 2100</b>. Participants with higher ratings can participate out of competition.
During the round, you will need to solve <b>6 problems</b>. You will have <b>2 hours</b> to solve them.
The problems for the round were prepared by [user:nik1998,2024-06-21], [user:egor4444ik,2024-06-21], [user:iamdimonis,2024-06-21] and me.
We sincerely thank everyone who provided invaluable assistance in preparing this round:
<ul style="list-style-type:square">
<li>Our insightful coordinator [user:74TrAkToR,2024-06-21] for excellent communication, helpful advice and assistance in problem preparation!</li>
<li>[user:Kolychestiy,2024-06-21] for improving one of the problems.</li>
<li>[user:EJIC_B_KEDAX,2024-06-21], [user:A_G,2024-06-21], [user:zw...
Announcement of Codeforces Round 955 (Div. 2, with prizes from NEAR!)
13.
Codeforces: Thanks for the support! <img src="/predownloaded/70/a9/70a96afc574eb7a6ee37d8a1ee175f91b2b3c83a.png" style="float: right; margin: 0 1em 1em 1em"/>
Hello!
This blog post is about the end of the crowdfunding campaign dedicated to the 8th anniversary of Codeforces. Everything worked out. Hooray!
For us, it is very important to support not only in terms of the collected budget, but as a powerful indicator that Codeforces is important to you. It was very pleasant to read words of gratitude and congratulations. Thank you!
We received more than 1000 donations from community members from around the world. For 45 days we've collected more than $60000 dollars. The collected funds will allow us to continue to move forward, to please you with new contests and improvements of the system.
I am happy to report that starting in May 2018, we will be able to slightly increase rewards for problem writers.
|Round type|USD|Rubles|
|-----------|--|---|
|Div 1 + Div 2| $250+*$150=$400 | 26000 rub |
| Div 2 | $1...
14.
Codeforces LATOKEN Round 1 (Div. 1 + Div. 2) Hello, Codeforces!
Welcome to the [contest:1534] supported by LATOKEN, that will start on [contest_time:1534]. It will be a combined rated round for both divisions (and div 3). **Please, note the unusual start time.**
All problems were created by [user:Aaeria,2021-06-09], [user:crackersamdjam,2021-06-12], [user:Dormi,2021-06-09], [user:Ninjaclasher,2021-06-09], and [user:Plasmatic,2021-06-09].
We would like to thank:
- Valentin Preobrazhenskiy from LATOKEN supporting the round.
- [user:300iq,2021-06-10] and [user:kan,2021-06-10] for coordinating the round and answering our relentless questions.
- [user:arvindr9,2021-06-09], [user:delmos,2021-06-09], [user:duality,2021-06-09], [user:growup974,2021-06-09], [user:m371,2021-06-09], [user:purplecrayon,2021-06-09], [user:rkm62,2021-06-09], [user:socho,2021-06-09], [user:wleung_bvg,2021-06-09], and [user:zeyu,2021-06-09] for their invaluable advice and suggestions.
- [user:MikeMirzayanov,2021-06-09] for great systems Codeforces...
just one year from its launch and 1m+ users in total. The emerging blockchain
based financial, over 600 000 app installs within just one year from its launch and 1m+ users
in total. The emerging
Announcement of Codeforces LATOKEN Round 1 (Div. 1 + Div. 2)
15.
Educational Codeforces Round 110 [Rated for Div. 2] Hello Codeforces!
On [contest_time:1535] [contest:1535] will start.
Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="http://codeforces.me/blog/entry/51208">blog post</a>.
This round will be **rated for the participants with rating lower than 2100**. It will be held on extended ICPC rules. The penalty for each incorrect submission until the submission with a full solution is 10 minutes. After the end of the contest you will have 12 hours to hack any solution you want. You will have access to copy any solution and test it locally.
You will be given **6 or 7 problems** and **2 hours** to solve them.
The problems were invented and prepared by Roman [user:Roms,2021-06-03] Glazov, Adilbek [user:adedalic,2021-06-03] Dalabaev, Vladimir [user:vovuh,2021-06-03] Petrov, Ivan [us...
Development** might be for you! This time we are looking for talented
individuals tolaunch our **new, /?utm_source=codeforces&utm_medium=partner&utm_campaign=both_b2c_front-end-
launch) сейчас, чтобы, =both_b2c_front-end-launch) to learn from the best in the field and kickstart
your career!_, =partner&utm_campaign=both_b2c_front-end-launch) сейчас, чтобы получить шанс
учиться у лучших в этой, launch our **new programme** with._ _We are offering up to a **50%
scholarship** for our Bachelor’s
Announcement of Educational Codeforces Round 110 (Rated for Div. 2)
16.
Order Capital Intro <img alt="Order Capital" src="/predownloaded/00/3e/003eef1043e9506ad4620583c5be192631830899.png" style="float:right;height: 200px; margin: 10px; max-width:40%;"/>
Hello everyone!
I invite you to take part in [contest:2122].
My name is Igor Pyshkin. Throughout my academic career, I participated in a lot of programming and math competitions: I am the 2016 ACM ICPC World Champion and competed in the onsite finals of the Facebook Hacker Cup, Google Code Jam, and TopCoder Open. After completing my degree, I transitioned into a new field — high-frequency trading (HFT).
Four years ago, I founded my own HFT fund — [Order Capital](https://ordercapital.com/). Since then together with my colleagues I have been working really hard to reach the highest levels of the HFT industry.
Launching this contest on Codeforces is quite special to me, as it is our first contest on the platform as a company.
I would like to thank the Codeforces team and everyone involved in the round preparation...
17.
Introducing Codeforge — launching October 12 Hello, Codeforces!
We, [Algolymp](https://www.algolymp.com/en), are a team of competitive programmers from Romania, and we’ve been working on [Codeforge](https://code.algolymp.com/codeforge-access), a multiplayer game built around solving algorithmic problems. Special thanks to [user:munteanuvlad98,2026-10-09] for coordinating this project.
The idea is simple: take the problem-solving we enjoy and give it more ways to be played together. Challenge a friend, compete as a team, enter a knockout tournament, or work through daily problems on your own.
What can you do in Codeforge?
- Solve daily challenges. Problems range from beginner-friendly exercises to IOI/ICPC-level challenges, whether you’re learning your first algorithms or preparing for your next contest.
- Play individual or team battles. Go head-to-head with another player, or team up with friends and compete against another team.
- Enter knockout tournaments. Compete individually or as a team, with each round de...
Codeforge [here](https://code.algolymp.com/codeforge-access) to join us when we
launch on October 12, launch on October 12.
18.
NBHEXT — Know Your Rating Few weeks ago there was yet another discussion about "omg why we wait for the rating updates so long!?!?!" in Russian version of CF. [user:MikeMirzayanov,2015-10-30] said that there are several reasons:
1. cheaters are checked manually;
2. rounds are usually held in the evening and Mike spends some time to get home from the University;
3. sometimes his little daughter asks him to play with her and Mike can't refuse of course
After [user:meh,2015-10-30], [user:MaximM,2015-10-30] and me read the third reason, we started to think what can be done about it. After a little thinking we came up with a solution that seemed to make contestants and Mike's daughter happy. The solution was a creation of browser extension that maintains rating changes of a current scoreboard whenever you refresh the result page. Something like this:
Luckily, CodeForces provided us with all the tools to make it happen: an API a...
19.
Data Structures and Algorithms Specialization at Coursera [fully launched] Last year we've won in Request for Proposals from Coursera, and this year we've launched the [Data Structures and Algorithms Specialization at Coursera](https://goo.gl/bpJ1KC). It is now the main option for studying algorithms and data structures on the platform. Specialization is a series of courses ending with a Capston Project which enables to learn the subject much deeper than it is usually possible in the scope of a massive online course.
The Specialization is launched by [University of California, San Diego](https://ucsd.edu) (Computer Science program ranked 11-th in the world) and the [Computer Science Department of Higher School of Economics](https://cs.hse.ru/en/):
1. Daniel Kane — Professor at [UCSD](https://ucsd.edu), Harvard graduate, PhD from MIT, four times Putnam fellow (US mathematical olympiad for university students), and there is even a [wikipedia article](https://goo.gl/vmFuJy) about him.
2. Pavel Pevzner — Professor at [UCSD](https://ucsd.edu), l...
20.
Are we close to machines solving ICPC problems? Hi, all,
I with few other folks at [NEAR](http://near.ai/blog) work on teaching machines to program. A particularly exciting sub-project of that is teaching machines to solve competitive programming problems.
In this post I would like to give a quick overview of where the state of the art is today, what the major challenges are, why this is not a popular area of research, and how the CodeForces community can help to address some of the issues the program synthesis community is facing today.
We also have a certain budged allocated for this project, and we are paying to the CodeForces members who help us with some data annotation challenges. We have paid more than $10k in our first two annotation projects, and are launching three more projects today. Scroll to the end if you are interested.
Competitive programming as a benchmark
======================================
With the emergence of deep learning, neural networks started performing almost at a human level in many ta...
21.
Nebius – Early Talents Hello, Codeforces! 👋
###We’re Nebius.
<img style="float: right; margin: 0 1em 0.5em 1em; width: 400px;"
src="/predownloaded/ac/09/ac09bf11e4b164fa4f62fcb418970a71dadb577a.jpg"
alt="NEBIUS color page">
You might remember our [Welcome Round](https://codeforces.me/blog/entry/113702) a few years ago, and we're back with another round! We invite you to take part in our Second round on Codeforces: [**Nebius Round 2** (Codeforces Round 1088, Div. 1 + Div. 2)](https://codeforces.me/contest/2211). Join us on [contest_time:2211] and test your skills by solving problems!
In the meantime, we want to share something big.
We’re launching our first [**Early Talent Program**](https://nebius.com/early-talent-program?utm_source=codeforces&utm_medium=job_board&utm_campaign=Early_Talent_Program) for students and recent grads.
Quick intro. I used to coordinate Codeforces rounds back in 2014–2015, did IOI/ICPC, and was pretty active here in the 2010s. Now I’m a Direc...
22.
Educational Codeforces Round 111 [Rated for Div. 2] Hello Codeforces!
On [contest_time:1550] [contest:1550] will start.
Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="http://codeforces.me/blog/entry/51208">blog post</a>.
This round will be **rated for the participants with rating lower than 2100**. It will be held on extended ICPC rules. The penalty for each incorrect submission until the submission with a full solution is 10 minutes. After the end of the contest you will have 12 hours to hack any solution you want. You will have access to copy any solution and test it locally.
You will be given **6 or 7 problems** and **2 hours** to solve them.
The problems were invented and prepared by Adilbek [user:adedalic,2021-07-13] Dalabaev, Vladimir [user:vovuh,2021-07-13] Petrov, Ivan [user:BledDest,2021-07-13] Androsov, Mak...
vibrant cities in the world._ _To celebrate our launch, we have **scholarships
available for our tech, _To celebrate our launch, we have **scholarships available for our tech
bachelor’s and master’s
Announcement of Educational Codeforces Round 111 (Rated for Div. 2)
23.
Codeforces Round #843. One of the contests authors decided to entertain again Hello, Codeforces! Codeforces #843 (Div. 2) round took place not so long ago, and I was one of its authors. When an hour had passed since the contest had started, I (you could say, by tradition) decided to enter the groups with cheaters and make fun of them once again.
And one more thing before we begin. [user:peltorator,2023-01-08] has launched a cool blog contest, I encourage everyone to participate: [blog](https://codeforces.me/blog/entry/110840).
Next. [user:COOLMAARK,2023-01-13], thanks for writing about the cheaters group, but it was better to do it not in the comments to the announcement, for not to advertise the group.
<spoiler summary="Comment under blog">
<a href="https://ibb.co/WtS5ZYz"><img src="https://i.ibb.co/NSwC5HN/pic1.png" alt="pic1" border="0"></a>
</spoiler>
Now to the point. So, since some cheaters recognize me, I invited [user:try_kuhn,2023-01-08] to help. In all the past cases, there was a problem: yes, sure, cheaters would submit the bad code, bu...
24.
Welcome to Bingo-CP Hello Codeforces!
Are you tired of only doing virtual contests? Want a more fun way to compete with friends, alone or on a team? Try Bingo-CP.
### What is Bingo-CP?
Bingo-CP is a free web app that turns Codeforces practice into a quick social game. Problems are placed on an n×n bingo board. Teams of 1–4 players compete at the same time. The first team to complete any row, column, or diagonal wins.
Try it: https://bingo-cp.vercel.app/home
### How to play
**1.** Click "Create Match" as in the picture.
**2.** Choose grid size (3×3 to 6×6), start time, duration, rating range, and mode.
**3.** Add team members by Codeforces handle (1–4 each).
**4.** Start the match. All teams solve at once. The first accepted submission claims the square for the team.
**5.** First team to complete a row, column, or diagonal wins.
Solves are detected automatically from Codeforces submissions, so no one needs to claim squares manually.
### Match options
Start time and du...
25.
User Lists Hello,
We are launching new feature on Codeforces, in early beta mode. I hope it will be useful to many active users of the web-site. Now you can create, manage and use the "user lists".
Partially, it is a kind of generalization of "friends." You can create a list of users interesting to you (you can create many lists) and, using the list, filter the results of rounds, quickly analyze what problems are solved in the problemset, etc. This feature is a helpful tool for coaching — I'm using it. By combining in a list of all practicing students, it is easy to pick up problems that have not been solved (and even not attempted) by any student.
A user list has name and a pair of two relatively secret keys & mdash; one for view/usage and one for editing. For example, here is the key to view a list of ACM-ICPC students at Saratov State U for autumn of 2015: 15c68c2cf878267d59373d1...
26.
CP-Algorithms: Discord server, donation campaign and more Hi everyone!
<img src="/predownloaded/82/15/821540e8f87d8a2b2d468377aacbba80b0aa1623.png" style="float:right;" width=100px>
It was a while since I [posted](https://codeforces.me/blog/entry/135081) last update about **[CP-Algorithms](https://cp-algorithms.com)**. As a general reminder, it is a community project that [started off](https://codeforces.me/blog/entry/13198) in 2014 by [user:RodionGork,2025-08-23] as a translation of [e-maxx](http://e-maxx.ru/), a Russian go-to resource at the time by [user:e-maxx,2025-08-23] for learning core competitive programming algorithms. Since then, CP-Algorithms grew quite a lot (which also prompted a rename from original project name `e-maxx-eng`) and includes a lot of new, original articles, and a lot of translated articles were enhanced and/or extended or even completely rewritten.
In this blog, I would like to share a bunch of updates about the site, to make sure it's still in the collective memory 😅
### New maintainers
...
27.
Educational Codeforces Round 136 [Rated for Div. 2] Hello Codeforces!
On [contest_time:1739] [contest:1739] will start.
Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="http://codeforces.me/blog/entry/51208">blog post</a>.
This round will be **rated for the participants with rating lower than 2100**. It will be held on extended ICPC rules. The penalty for each incorrect submission until the submission with a full solution is 10 minutes. After the end of the contest you will have 12 hours to hack any solution you want. You will have access to copy any solution and test it locally.
You will be given **6 or 7 problems** and **2 hours** to solve them.
The problems were invented and prepared by Adilbek [user:adedalic,2022-09-28] Dalabaev, Vladimir [user:vovuh,2022-09-28] Petrov, Ivan [user:BledDest,2022-09-28] Androsov, Mak...
Announcement of Educational Codeforces Round 136 (Rated for Div. 2)
28.
Codeforces Round 1028 (Div.1, Div.2) Editorial You could tell people didn't seem to like the match very much. I'm sorry I screwed up again ¯\\_(ツ)_/¯
If you're interested, I'd like to share some thoughts I have about this contest.
<spoiler summary="sad story">
This time I've been trying my best to make the problems use more varied algorithms instead of just dp problems, but sadly [problem:2115C] was much harder than expected.
But it seems like people are complaining more about the narrow time limit, centered on [problem:2116C] and [problem:2115C].
No one realized this before the contest, because none of the tester's code is get TLE except the wrong time complexity.
I actually don't see a problem with the Time Limit of [problem:2116C]. Some of you may be puzzled, but let me try to explain this:
- The intended solution is $O(\sum n \max(a) + \max(a)^2)$ and does not contain $\log \max(a)$. Computing $\gcd(x, y)$ is not $O(1)$, if you don't preprocess, then it's not unusual to actually get a TLE.
- I believe the v...
(h_i - l)$. For the first $s$ times the sword doesn't shine, Gellyfish will
obviouslylaunch an
Tutorial of Codeforces Round 1028 (Div. 1)
Tutorial of Codeforces Round 1028 (Div. 2)
29.
8VC Venture Cup Announcement <img src="http://assets.codeforces.com/images/8vc/8vc-venturecup-logo.png" style="float:right;margin:0 1em 1em 1em"/>
Hey Codeforces!
I’ve worked with Addepar and the broader 8 | family of companies in Silicon Valley throughout 2014 and 2015, and it’s been an excellent experience. I would encourage everyone in the community to learn more about the great work that these companies are doing and I’m happy to announce that 8 | Partners will be hosting the 8 | VC VentureCup on Codeforces! It’ll be a fun contest and I’ve worked on the problems along with a few competitive programmers in our network. The contest will begin on February 13 and consist of two rounds.
##### ABOUT 8 | PARTNERS
<a href="http://eight.vc/">8 | Partners</a>, which consists of Joe Lonsdale (co-founder of Palantir) and his core team from Formation | 8, is a Silicon Valley venture capital firm that invests in industry-transforming technology companies. The team's investment portfolio includes companies suc...
30.
Harbour.Space Scholarship Contest 2023-2024 (Div. 1 + Div. 2) Editorial Thank you for participation and we hope you enjoy this round ヽ(^ o ^)/.
During the contest, there was a small issue in problem D. For those affected, we have skipped your duplicate submissions (if your duplicate submissions were not skipped, please let us know). We apologize again for any inconvenience caused.
In addition, we are honored to invite you to our unofficial round tomorrow (*╹▽╹*) [Invitation to TheForces Round #22 (Interesting-Forces)](https://mirror.codeforces.com/blog/entry/119771)
### [1864A-Increasing and Decreasing](https://mirror.codeforces.com/contest/1864/problem/A)
Idea : [user:wuhudsm,2023-08-27]
<spoiler summary="Tutorial">
We use the following greedy construction:
For all $i$ ($1<i<n$), set $a_i=a_{i+1}-(n-i)$. If $a_2-a_1 \geq n-1$, we've found a solution, otherwise there is no solution.
Proof. Assume there's a solution which includes an index $i$ ($1<i<n$) such that $a_{i+1}-a_i>n-i$. We can make $a_j:=a_j+\Delta$ for all $j$ ($2 \le j ...
One of the things we need to do is to launch the BFS from the new connected
components which arise
31.
Invitation to CodeChef July CookOff 2021 (with prizes!) We invite you to participate in CodeChef’s [July Cookoff](https://www.codechef.com/COOK131?utm_source=codeforces_blog&utm_medium=organic&utm_campaign=JulyCook), today — 28th July, from [8:00 PM — 10:30 PM IST](https://www.timeanddate.com/worldclock/fixedtime.html?msg=July+Cook-off+2021&iso=20210728T2000&p1=44&ah=2&am=30). **Note the unusual time**.
There will be **7 problems** in all divisions.
The contest will be rated for all three Divisions. The July Cook-Off also marks the launch of our new prize structure for global & Indian participants. More details are given below.
Joining us on the problem setting panel are:
- Contest Admins: Ashish [user:ashishgup,2020-12-19] Gupta and Jatin [user:jtnydv25,2021-05-30] Yadav
- Head Admin: Alex [user:Um_nik,2021-06-26] Danilyuk
- Tester: Aryan [user:aryanc403,2021-07-28] Choudhary
- Statement Verifier: Riley [user:1-gon,2021-07-28] Borgard
- Editorialist: Vichitr [user:Vichitr,2021-07-28] Gandas, Srikkanth [u...
The contest will be rated for all three Divisions. The July Cook-Off also marks
thelaunch of our, launch of our new prize structure for global & Indian participants. More
details are given below
32.
Launch of CodeIt::Suisse 2020 Credit Suisse is conducting an annual hackathon facing to University students as usual, though this year will be virtual due to COVID situation in Hong Kong.
Targetted audience
------------------
The contest is open to all full-time University students studying in Singapore / Hong Kong graduating in 2021 — 2024, either UG or TPG.
Dates
-----
Registration deadline is on 13th September, the entire event will be conducted between **25 afternoon — 27 afternoon --** Make sure you are available for the entire weekend!
Prizes
-----------------------------------------------------------------------------------------------------------
Site / 1st / 2nd / 3rd | **HKG(HKD) / 12500** / 7800 / 5100 | **SGP(SGD) / 2200** / 1400 / 950.
Due to SGP laws, the host cannot giveaway cash prices without being taxed, so prizes are given with items of equivalent market value (2018 prize: iPad 6 x3, 2019 prize: Electronic product vouchers). There are also policies preventin...
Launch of CodeIt::Suisse 2020, /recruitment-technology-microsite/technology-buzz/launch
-2020-codeit-suisse.html) . From past years experiences, /technology-buzz/launch-2020-codeit-suisse.html) . From past years experiences
the application is highly
33.
Solve problems for a chance at an interview with Google A couple of years ago Google launched an interesting website: [Google
Foobar](https://www.google.com/foobar/). If you try to log in, you'll get an
error saying:
To login, you have to have logged in before. Confused? Search on...
Pretty mysterious, right? Well, from what I read on Hacker News at the time,
this is some kind of a puzzle set up by Google to recruit Python and Java
developers. To get in, you'd simply have to search for the correct phrase.
Someone reported that searching for "arraylist java" got him inside, but that
didn't work for me.
However, I recently found that searching for this actually gets you inside, but
you have to be a little bit patient. Here's what you can do:
1. Open a browser of your choice (it has to be a sufficiently new version so
you get the newest version of Google). I've only tested this successfully
with Chrome and Firefox.
2. Go to [https://google.com/ncr](https://google.com/ncr). (The /ncr at the end
is to make s...
34.
OpenAI o1 IOI submissions Hi Codeforces! I am a member of the reasoning team at OpenAI. We are especially excited to see your interest in the OpenAI o1 model launch, many of us being Codeforces users ourselves ([user:chenmark,2024-09-17], [user:meret,2024-09-17], [user:qwerty787788,2024-09-17], among others). Given the curiosity around the IOI results, we wanted to share the submissions that scored 362.14—above the gold medal threshold—from the [research blog post](https://openai.com/index/learning-to-reason-with-llms/) with you. These were the highest scoring among 10,000 submissions, so still a ways to go until top human performance, but we aspire to be there one day.
The following C++ programs (including comments!) are written entirely by the model. Special thanks to [user:PavelKunyavskiy,2024-09-17] for maintaining the IOI mirror, which we used to check our scores. We hope you enjoy taking a look!
**nile (100/100)**
- [Submission](https://gist.github.com/aw31/2500acc418419e022021617170cbfc9f#file-n...
interest in the OpenAI o1 model launch, many of us being Codeforces users
ourselves ([user:chenmark
35.
mBIT 2025 Editorial Thank you to everyone who competed in mBIT 2025! It was a record breaking year for us with 84 in-person participants and 135 online participants. We hoped you guys enjoyed it as much as we did.
We tried hard to make the problems fun and interesting for as wide of a skill gap as possible. In fact, this year's competition had an in-person team of middle schoolers that was unfamiliar with for loops, and an online team with all three participants in the top 15 in the world in codeforces. We are glad to contribute to all niches of the computer science community: beginner and advanced, local and global. Thank you all for your enthusiasm.
Congratulations to the winners:
**Online Advanced:**
- 1st place — HoMaMaOvo — Masaki Nishimoto, Riku Kawasaki, Yui Hosaka
- 2nd place — mathforcesbox — Brian Xue, Bing-Dong Liu, Alex Chen
- 3rd place — bluepuppygreenturtle — Rain Jiang, Kai Jiang
**Online Intermediate:**
- 1st place — NULP Lega...
presence of firecrackers at a lower height. Thus, by having firecrackers launch
from top to bottom, represent whether each x-coordinate is blocked from launch with a segment tree
(or a fenwick tree) on all
36.
Invitation to CodeChef August CookOff 2021 (with prizes!) We invite you to participate in CodeChef’s [August Cookoff](https://www.codechef.com/COOK132?utm_source=codeforces_blog&utm_medium=organic&utm_campaign=AugustCook), today — 22nd August, from [9:30 PM — 12:30AM IST](https://www.timeanddate.com/worldclock/fixedtime.html?msg=August+Cook-off+2021&iso=20210822T2130&p1=44&ah=3).
The contest will be **3 hours long**. There will be **7 problems** in Div 1/2 and **8 problems** in Div 3.
The contest will be rated for all three Divisions. The July Cook-Off also marks the launch of our new prize structure for global & Indian participants. More details are given below.
Joining us on the problem setting panel are:
- Contest Admins: Ashish [user:ashishgup,2020-12-19] Gupta.
- Head Admin: Alex [user:Um_nik,2021-06-26] Danilyuk
- Tester: Shubham [user:TheOneYouWant,2021-08-22] Jain
- Setters: Soumyadeep [user:palsoumyadeep,2021-08-22] Pal, Aryan Agarwala, Deepak [user:Deepak_23,2021-08-22] Barnwal, Vishesh [user:vishes...
Divisions. The July Cook-Off also marks the launch of our new prize structure
for global & Indian, The contest will be rated for all three Divisions. The July Cook-Off also marks
thelaunch of our
37.
CodeDrills — A new online judge We are going through an unprecedented situation currently. There are lockdowns and quarantines in many parts of the world. We feel the best way to cope with everything that is going on is to keep ourselves occupied.
To help with that, we at CodeDrills have something for all the competitive coders out there. On 25th March, we launched our own online judge and also launched the CodeDrills covid 21 days challenge. Every day, for the 21 days starting from 25th March, we will upload 1 problem. Just visit [codedrills.io](https://codedrills.io), login and start solving! The launch coincided with the start of a full lockdown in India.
Since the situation was unexpected, we rushed to put up the site as soon as possible, so there might be issues. If you find any bugs or want to request a feature, please write to us at [email protected] with as much details as possible.
Here is our mascot Ufu wearing a mask (if you are unable to see him here, head over to [our page](https://codedrills...
[codedrills.io](https://codedrills.io), login and start solving! The launch
coincided with the start of a full, . Just visit [codedrills.io](https://codedrills.io), login and start solving!
Thelaunch coincided with
38.
CodeHunt: A Site for Problem Filtering and User Comparison Hi Coders! We have launched **[CodeHunt](https://codehunt.cc)**!
**[CodeHunt](https://codehunt.cc)** is made to help **Codeforces** and **UVa Online Judge** users filter their problems with convenience and ease. You can also compare yourself with friends and rivals to motivate your practice and growth.
What inspired us to make CodeHunt?
----------------------------------
Before any other site, we practiced our competitive programming using **UVa**, assisted, of course, by the incredible site, [uHunt](https://uhunt.onlinejudge.org/), made by _Felix Halim_. As we began to participate in **Codeforces** contests and solved more and more problems here, we never had the same level of motivation for the long grind as we did when using **uHunt**. We realized it was because there wasn’t a tool out there for **Codeforces** that was as convenient in tracking problems.
After a while of looking for the right tool...
39.
Refact.AI Matches <img src="/predownloaded/11/18/111879e63c0725e4d5f3ad8a35f1c4a37a2f927e.png" style="float:right; margin: 0 0 2em 2em; width:300px;"/>
Hello, Codeforces.
We're Refact.ai, an open-source AI Coding Assistant, and on November 9th, we'll be hosting our first round on Codeforces! It will be a combined Div.1+Div.2 round. Welcome!
The winners will receive valuable prizes, and all participants will have a chance to get some exclusive merch from us.
Refact.ai is pushing AI beyond simple code completion. Soon, we'll launch the Autonomous AI Agent—a developer's buddy that handles real engineering tasks end-to-end, from planning and coding to testing and deployment.
If you're excited about AI in software development and want to build the future instead of focusing on the trivial, join Refact.ai, founded by a former OpenAI researcher. We're looking for talented Researchers and Backend developers to join our team.
We already have competitive programmers on board, such as [user:humbe...
completion. Soon, we'll launch the Autonomous AI Agent—a developer's buddy
that handles real, Refact.ai is pushing AI beyond simple code completion. Soon, we'll launch the
Autonomous AI Agent—a
40.
CP Editor 2.0.3 : Everything you wanted is here Check : https://cpeditor.github.io
==================
Hi Guys !
Around a week ago, I released the first version of CP Editor. If you are reading about CP Editor for first time. I request you to read my [previous blog](https://codeforces.me/blog/entry/71673) first.
Many user liked it and I got many suggestions about enhancements and some bug reports as well. I liked your over whelming response, it made me happy. Now it's time for me to make you happy.
Enough talking, let's get into what's new in CP Editor 2.0. It is a big release and hence a long blog ;-)
##### Dark theme
Last time there was a dark theme but it only made the editor dark. So, it wasn't truly dark theme. Now with this new release CP Editor packs a system-wide dark theme. Have a look here
##### Dependency Updates
Just like any other software, CP Editor also have a long acyclic dependencies, and over the weeks many were updat...
Flashing of Command Window, when You Launch/Update Settings. - Added, Editor
will save your file as soon, has been added that checks for newer releases of the editor after every launch
of Editor. If a new, An Updater has been added that checks for newer releases of the editor after
everylaunch of Editor
41.
TheForces Round #44 (DIV3.5-Forces, TheForces Rated, Prizes!) Hello, Codeforces!
We are happy to invite you to [**TheForces Round #44 (DIV3.5-Forces)**](https://codeforces.me/contestInvitation/fa49752704e242f1bfee8cdbb49519302d5c6e47), which will take place on **[contest_time:106049]**
<spoiler summary="What is TheForces Round?">
TheForces is a project uniting individuals with a shared interest in competitive programming contests. You can join our discord server with more than $2500$ members to communicate with founders and members of TheForces.
In the other words TheForces rounds are series of educational contests for beginners to masters which are created by a group of CP lovers in the CF community, It's where anyone can propose and prepare his own interesting problems and receive money!
Not to mention that we've already created **two** official codeforces Div($1 + 2$) rounds before ;) So join us now!
[Discord link](https://discord.com/servers/theforces-901910143342608405)
[TheForces website](https://theforces.netlify....
Announcement of TheForces Round #44 (DIV3.5-Forces)
42.
Getting ready for ACM-ICPC 2016-2017: weekly trainings on Codeforces <img src="http://worker.codeforces.ru/static/images/icpc/icpc_logo.png" style="float:right;margin:0.5em 1em 1em 1em;"/>
The new season of a collegiate team championship ACM-ICPC is about to start. For example, the registration for the Southern (Saratov) Subregional Contest is already running. I am sure that many participants of the Codeforces rounds will take part in ACM-ICPC this year.
We are launching a series of weekly practice trainings on Codeforces. Naturally, they will be held within Codeforces::Gym. Feel free to participate!
The practice starts on Wednesdays at about 13:10 PM (UTC), which is 16:10 Moscow Time. Expected duration is 4-5 hours. We are going to practice using the problems of different contests of the past years. All you need is common sense and observing these simple rules:
- We will not publish the problem source before the practice starts. We want you to solve the problems on your own in a fair competition. If you use somebody else’s code or cheat in...
43.
TheForces Round #45 (DIV3-Forces2, TheForces Rated, Prizes!) Hello, Codeforces!
We are happy to invite you to [**TheForces Round #45 (DIV3-Forces2)**](https://codeforces.me/contestInvitation/2dc50117b1117d7ca1b044a747e210ad5278a12d), which will take place on **[contest_time:106177]**
<spoiler summary="What is TheForces Round?">
TheForces is a project uniting individuals with a shared interest in competitive programming contests. You can join our discord server with more than $2500$ members to communicate with founders and members of TheForces.
In the other words TheForces rounds are series of educational contests for beginners to masters which are created by a group of CP lovers in the CF community, It's where anyone can propose and prepare his own interesting problems and receive money!
Not to mention that we've already created **two** official codeforces Div($1 + 2$) rounds before ;) So join us now!
[Discord link](https://discord.com/servers/theforces-901910143342608405)
[TheForces website](https://theforces.netlify.a...
44.
[Tutorial] Quick start in solving problems on GPU + CPU Hello, codeforces!
Do you have modern GPU and CPU and want to calculate something with them, but you don't know how to do it? Dont be upset, because you can read this blog and run your first GPU program on your AMD/Intel/NVIDIA GPU. I will describe an installation process and then we will dive into the C++ code. As an example, we will calculate a lot of mazes for [Bug Game](https://codeforces.me/blog/entry/115144) in parallel. For doing this in simple way, we will use library [Boost.Compute](https://www.boost.org/doc/libs/1_80_0/libs/compute/doc/html/index.html), which is a C++ STL-style wrapper over OpenCL library.
[cut]
...
Installation for MacOS (Apple M1 Pro)
==================
As [user:Gosunov,2023-06-10] said, `OpenCL` and `g++` are pre-installed on `MacOS`. Everything that you have to do is install `Boost` with command `brew install boost`. After this you will be able to compile your program with command `g++ -std=c++17 -O3 -I/opt/homebrew/Cellar/boost/1.81.0_1/...
45.
Invitation to TheForces Round #39 (1000-Forces, TheForces Rated, Prizes!) Hello, Codeforces!
We are happy to invite you to [**TheForces Round #39 (1000-Forces)**](https://codeforces.me/contestInvitation/19cfbb125a2eb91d20e8e0a3c6260d4adde8a6c6), which will take place on **[contest_time:105672]**
<spoiler summary="What is TheForces Round?">
TheForces is a project uniting individuals with a shared interest in competitive programming contests. You can join our discord server with more than $2500$ members to communicate with founders and members of TheForces.
In the other words TheForces rounds are series of educational contests for beginners to masters which are created by a group of CP lovers in the CF community, It's where anyone can propose and prepare his own interesting problems and receive money!
Not to mention that we've already created **two** official codeforces Div($1 + 2$) rounds before ;) So join us now!
[Discord link](https://discord.com/servers/theforces-901910143342608405)
[TheForces website](https://theforces.netlify.app/)
...
Announcement of TheForces Round #39 (1000-Forces)
46.
Order Capital is back with Round 2 <img alt="Order Capital" src="/predownloaded/00/3e/003eef1043e9506ad4620583c5be192631830899.png" style="float:right;height: 200px; margin: 10px; max-width:40%;"/>
### 👋Yo Codeforces!
Hello from **Order Capital**!
Last year we launched our very [first Codeforces contest](https://codeforces.me/blog/entry/144537) and the response was way beyond our expectations.
So we had no choice but to run it back!
For those who don’t know us yet:
[Order Capital](https://ordercapital.com/) is a group of companies specializing in software development and automated trading. We combine modern technology and research to make data-driven decisions in quantitative trading and explore new opportunities for business growth.
🚀 Introducing: [contest:2237].
This time we’ve prepared:
- a new set of problems;
- plenty of interesting ideas;
- a few unexpected twists.
Whether you're aiming for a new rating milestone, looking for a good challenge, or simply enjoy...
47.
TheForces Round #43 (DIV2-Forces, TheForces Rated, Prizes!) Hello, Codeforces!
We are happy to invite you to [**TheForces Round #43 (DIV2-Forces)**](https://codeforces.me/contestInvitation/3410fdc34789c0176f60676a4d22dfcb5980a321), which will take place on **[contest_time:106014]**
At the same time, we welcome you to participate in the **official** DIV1/DIV2 round scheduled on the 31st!
<spoiler summary="What is TheForces Round?">
TheForces is a project uniting individuals with a shared interest in competitive programming contests. You can join our discord server with more than $2500$ members to communicate with founders and members of TheForces.
In the other words TheForces rounds are series of educational contests for beginners to masters which are created by a group of CP lovers in the CF community, It's where anyone can propose and prepare his own interesting problems and receive money!
Not to mention that we've already created **two** official codeforces Div($1 + 2$) rounds before ;) So join us now!
[Discord link]...
Announcement of TheForces Round #43 (DIV2-Forces)
48.
Midnight Code Cup is here <img alt="Neapolis University Pafos" src="/predownloaded/09/67/0967c4495a0c7e09b4854a493404ed57e3fecbe2.png" style="float:right;height: 150px; margin: 10px;"/>
**The Qualification round has started! Cheer for your favourite team:** https://ranker.codeforces.com/ranklist/602915
We’re excited to launch the first-ever Midnight Code Cup (MCC) — a team competition featuring an online Qualification round and a 24-hour onsite Final. Expect algorithmic challenges, optimization puzzles, cutting-edge computer science, and some just plain weird problems. It’ll be exhausting. And fun.
Who are we?
-----------
A team of problem solving <s>geeks</s> <s>veterans</s> enthusiasts, eager for the return of this contest format. The idea of Midnight Code Cup was born at **Recraft.AI** (AI image generation and graphic design pioneers) with huge support from **JetBrains** (creator of Kotlin, intelligent IDEs, and AI-driven developer tools) as well as **Neon** (developer-first open-source database)...
to launch the first-ever Midnight Code Cup (MCC) — a team competition
featuring an online, We’re excited to launch the first-ever Midnight Code Cup (MCC) — a team
competition featuring an
49.
Getting ready for ACM-ICPC 2014-2015: weekly trainings on Codeforces <img src="http://worker.codeforces.ru/static/images/icpc/icpc_logo.png" style="float:right;margin:0.5em 1em 1em 1em;"/>
The new season of a collegiate team championship ACM-ICPC is about to start. For example, the registration for the Southern (Saratov) Subregional Contest is already running. I am sure that many participants of the Codeforces rounds will take part in ACM-ICPC this year.
We are launching a series of weekly practice trainings on Codeforces. Naturally, they will be held within Codeforces::Gym. Feel free to participate!
The practice starts on Thursdays at about 12:10 PM (UTC), which is 16:10 Moscow Time. Expected duration is 4-5 hours. We are going to practice using the problems of different contests of the past years. All you need is common sense and observing these simple rules:
- We will not publish the problem source before the practice starts. We want you to solve the problems on your own in a fair competition. If you use somebody else’s code or cheat in ...
50.
Invitation to Insomnia'25 **Greetings, Codeforces Community!**
====================================
We, [the Programming and Algorithms Group](https://www.instagram.com/pag_iitr/), are excited to invite you to our upcoming event, **Insomnia 2025!** This event is proudly sponsored by [Hilabs](https://www.hilabs.com/) as our title sponsor, with support from our cherished alumni as co-sponsors.
**Format**
----------
**Insomnia 2025** is an ICPC style team contest where you would be given 10-15 problems in the span of 5 hours, for teams of at most 3 members.
- **Date & Time**: [Saturday, March 1, 2025, at 20:00 IST](https://www.timeanddate.com/countdown/launch?iso=20250301T20&p0=1863&msg=Insomnia+2025&font=cursive)
- **Mode**: Online
- **Platform**: Codeforces, [Contest Link](https://codeforces.me/contestInvitation/29f652a20cd24fa942defdf237dc5a72e416d1a1)
- [Registration Link](https://unstop.com/p/insomnia25-program...
/launch?iso=20250301T20&p0=1863&msg=Insomnia+2025&font=cursive) - **Mode**:
Online - **Platform, ://www.timeanddate.com/countdown/launch
?iso=20250301T20&p0=1863&msg=Insomnia+2025&font=cursive) - **Mode
Announcement of Insomnia 2025
51.
Invitation to TheForces Round #41 (Magical-Forces, TheForces Rated, Prizes!) Hello, Codeforces!
<div style="text-align: center;">
<img src="https://s2.loli.net/2025/03/30/g3ov1BSIcrqseOf.png" alt="示例图片">
</div>
We are happy to invite you to [**TheForces Round #41 (Magical-Forces)**](https://codeforces.me/contestInvitation/f9d058e868f71c9dcb6eef79c97796e0c5e7c76c), which will take place on **[contest_time:105805]**
**UPD: Due to a conflict with the AtCoder round, the start time has been postponed by 30 minutes.**
<spoiler summary="What is TheForces Round?">
TheForces is a project uniting individuals with a shared interest in competitive programming contests. You can join our discord server with more than $2500$ members to communicate with founders and members of TheForces.
In the other words TheForces rounds are series of educational contests for beginners to masters which are created by a group of CP lovers in the CF community, It's where anyone can propose and prepare his own interesting problems and receive money!
Not to mention ...
Announcement of TheForces Round #41 (Magical-Forces)
52.
Invitation to TheForces Round #40 (Maths-Forces, TheForces Rated, Prizes!) Hello, Codeforces!
We are happy to invite you to [**TheForces Round #40 (Maths-Forces)**](https://mirror.codeforces.com/contestInvitation/910bff61a51f15df4e7282097ee6aad30a75e44d), which will take place on **[contest_time:105767]**
<spoiler summary="What is TheForces Round?">
TheForces is a project uniting individuals with a shared interest in competitive programming contests. You can join our discord server with more than $2500$ members to communicate with founders and members of TheForces.
In the other words TheForces rounds are series of educational contests for beginners to masters which are created by a group of CP lovers in the CF community, It's where anyone can propose and prepare his own interesting problems and receive money!
Not to mention that we've already created **two** official codeforces Div($1 + 2$) rounds before ;) So join us now!
[Discord link](https://discord.com/servers/theforces-901910143342608405)
[TheForces website](https://theforces.netlif...
Announcement of TheForces Round #40 (Maths-Forces)
53.
Advanced Algorithms and Complexity Course I [wrote](http://codeforces.me/blog/entry/44924) in May about the launch of [Data Structures and Algorithms](https://goo.gl/jV5fbe) Specialization at Coursera. In September, the [Advanced Algorithms and Complexity](https://goo.gl/TalA42) Course of this Specialization was launched, and I'd like to tell you more about it.
Course topics:
1. Network Flows (Ford-Fulkerson and Edmonds-Karp algorithms).
1. Linear Programming (the Simplex Method).
1. NP-completeness (theory, reductions, solving NP-complete problems using SAT-solvers).
1. Coping with NP-completeness (bruteforce optimizations, solvable cases, approximation algorithms).
1. Streaming Algorithms.
The problems for this course were prepared by [user:ifsmirnov,2016-10-03], [user:Ilyakor,2016-10-03], [user:Michael,2016-10-03], [user:Perlik,2016-10-03], [user:romanandreev,2016-10-03], [user:Zlobober,2016-10-03] and Paul Melnichuk.
Network flows and the algorithms covered in the Specialization can sound as not very advan...
I [wrote](http://codeforces.me/blog/entry/44924) in May about the launch of
[Data Structures and
54.
Cognition, competitive programmers, and Devin, the first AI software engineer I am really excited to see a startup, built by mostly competitive programmers, launching a demonstration of which is the state-of-the-art.
You can watch their demo of Devin, the first AI software engineer, here
- https://twitter.com/cognition_labs/status/1767548763134964000
You can read the opinions of an external user who has early access here
- https://twitter.com/itsandrewgao/status/1767576901088919897
This is an article from Bloomberg (paywall)
- https://www.bloomberg.com/news/articles/2024-03-12/cognition-ai-is-a-peter-thiel-backed-coding-assistant
These are the competitive programmers involved
- Neal Wu [user:neal,2024-03-13] | IOI 3 Gold
- Scott Wu [user:scott_wu,2024-03-13] | IOI 3 Gold
- Andrew He [user:ecnerwala,2024-03-13] | IOI 2 Gold
- Steven Hao [user:stevenkplus,2024-03-13] | IOI 1 Gold 1 Sliver
- Walden Yan [user:walnutwaldo20,2024-03-13] | IOI 1 Gold
- Adhyyan Sekhsaria [user:AsleepAdhyyan,2024-03-13] | IOI 1 Silver
There have been [many...
55.
TheForces Round #42 (Ultimate-Answer-Forces, TheForces Rated, Prizes!) Hello, Codeforces!
We are happy to invite you to [**TheForces Round #42 (Ultimate-Answer-Forces)**](https://codeforces.me/contestInvitation/2f00d5af212537b8492b56c09a21186f8994c4c2), which will take place on **[contest_time:105846]**
[The source of the name]
(https://en.wikipedia.org/wiki/Phrases_from_The_Hitchhiker%27s_Guide_to_the_Galaxy#The_Answer_to_the_Ultimate_Question_of_Life,_the_Universe,_and_Everything_is_42)
<spoiler summary="What is TheForces Round?">
TheForces is a project uniting individuals with a shared interest in competitive programming contests. You can join our discord server with more than $2500$ members to communicate with founders and members of TheForces.
In the other words TheForces rounds are series of educational contests for beginners to masters which are created by a group of CP lovers in the CF community, It's where anyone can propose and prepare his own interesting problems and receive money!
Not to mention that we've already created...
Announcement of TheForces Round #42 (Ultimate-Answer-Forces)
56.
MathForces: Math Olympiad ELO Rating (Proof-based!) Hey! Wanted to share with you all the launch of the MathDash Math Olympiad Rating and Leaderboard!
<b>Proof-based competition:</b> Solve and prove each question.
<b>Problem difficulties:</b> The six problems on a recent International Math Olympiad should be ratings ~2100/2500/3000/2100/2500/3000. Rating 1000 should be approachable for anyone with any math background!
<b>Grading:</b> Submissions graded ASAP (likely after the round).
<b>Regrade policy:</b> Dispute scores in the post-contest discussion chat. Grading is at our discretion.
Good luck and happy solving!
[(1200) Olympiad 2 — Problem 1](https://mathdash.live/contest/olympiad-2-p1) <br />
[(1200) Positive Sum In Collection](https://mathdash.live/contest/proof-problem-6957406043) <br />
[(1400) Planet Htrae](https://mathdash.live/contest/proof-problem-7562553459) <br />
[(1400) Round Table](https://mathdash.live/contest/proof-problem-5097635854) <br />
[(1400) Product in Grid](https://mathdash.live/con...
Hey! Wanted to share with you all the launch of the MathDash Math Olympiad
Rating and Leaderboard
57.
Submitter Hello!
I am introducing a new tool for competitive programming—submitter. It does just that, submits your solution to supported online judges and displays results, all (mostly) from the comfort of your command line. I've completely rewritten it to get rid of using Selenium.
## Installation
### Pre-built binaries
Grab the latest binary for your platform from the [releases page](https://github.com/EgorKulikov/submitter/releases/latest):
- **Linux (Debian/Ubuntu)**: `submitter_<version>_amd64.deb` — `sudo dpkg -i submitter_*.deb`
- **macOS (Apple Silicon)**: `submitter-<version>-aarch64-macos.dmg` — open and copy `submitter` to a directory on your `PATH`. The binary is unsigned; on first launch, right-click → Open to bypass Gatekeeper.
- **Windows**: `submitter-<version>-x86_64-windows.exe` — place anywhere on your `PATH`.
### From source
You would need [rust](https://www.rust-lang.org/tools/install)
```
cargo install --git https://github.com/EgorKulikov/submitt...
directory on your `PATH`. The binary is unsigned; on first launch, right-click
→ Open to bypass, ; on first launch, right-click → Open to bypass Gatekeeper. - **Windows**:
`submitter-
58.
Algoritmi Competitive Programming Academy Hello Codeforces Community,
I am _AmirReza PourAkhavan_,
- Over **8** years of teaching experience, including teaching at the Iran Team Selection Camp for **IOI**.
- Contest coordinator at LeetCode and formerly, **Codeforces**.
- ICPC World Finalist (twice) and took a high-honored place, **24**.
- Solved over **5000** problems on various platforms.
Along with my dedicated team, I am thrilled to introduce our new project focused on developing the next generation of competitive programmers. Having competed in and coached teams for the Iranian and International Olympiads in Informatics, we have experienced firsthand the significant impact of competitive programming. It is with great enthusiasm that we are launching an affordable, high-quality training program to prepare ambitious individuals for the challenges and opportunities of **IOI** and other competitive programming contests, like **ICPC**.
<center>
<br>
<img width="30%" src="/predownloaded/b6/f5/b6f5012e2a5f7ce09...
59.
CP-31 Sheet by TLE Eliminators | Handpicked Problems from 800 to 1900 Rating Hi folks! I have created a list of 31 problems in each rating from 800 to 1900 with nice reusable concepts.
Link to the sheet: https://www.tle-eliminators.com/cp-sheet
#### Who Am I?
<spoiler summary="">
- My name is Priyansh Agarwal. I have been in this space for 5+ years. I have solved 4k+ programming problems on online judges. I am an [ICPC World Finalist](https://x.com/Priyansh_31Dec/status/1782293445723488287) and have secured [Rank 6 in a Google Kick Start round](https://x.com/Priyansh_31Dec/status/1505416520595173377).
- I have created a lot of CP tutorials on my [Youtube channel 70k+](https://www.youtube.com/@PriyanshAgarwal) and [TLE's Youtube channel 35k+](https://www.youtube.com/@TLE_Eliminators) where we have posted 300+ post contest discussions of contests from Codeforces, Codechef and Leetcode to help people upsolve contests.
- I have been running a competitive programming training for beginners called TLE Eliminators for the last 4 years, where we've taught 1...
60.
Codeforces Round #448(Div.2) Hi everyone!
Codeforces Round #448 (Div.2) takes place on [26th of November at 19:05 MSK](https://www.timeanddate.com/countdown/launch?iso=20171126T1905&p0=285&msg=Codeforces+Round+%23448&font=cursive). As usual, Div.1 participants can join out of competition.
This is my second round on Codeforces! I advise you to read all of the 5 problems. Hope everyone will find something interesting.
I'd like to thank [user:gritukan,2017-11-25] for coordination, [user:igdor99,2017-11-25] for helping me in developing problems. And, surely, thanks to [user:Tommyr7,2017-11-26], [user:Arpa,2017-11-26], [user:gainullin.ildar,2017-11-26] for testing this round.
Of course, many thanks to [user:MikeMirzayanov,2017-11-25] for great Codeforces and Polygon platforms.
Scoring: **500-1000-1750-2000-2250**
High ratings to everybody!
**UPD:** Contest is finished. Editorial will be posted soon.
**UPD:** [Editorial](http://codeforces.me/blog/entry/56028)
Congratulations to the winners!!!...
://www.timeanddate.com/countdown/launch
?iso=20171126T1905&p0=285&msg=Codeforces+Round+%23448&font, [26 ноября в 19:05 MSK](https://www.timeanddate.com/countdown/launch
?iso=20171126T1905&p0=285&msg, Всем привет! [26 ноября в 19:05 MSK](https://www.timeanddate.com/countdown/
launch?iso
Announcement of Codeforces Round 448 (Div. 2)
61.
Codeforces: the Results of 2012 Happy New Year!
The New Year is in a two-day distance from us and it's good time to summarize the ending year. In a nutshell, this year's been highly productive for the project. Codeforces has set up large championships, rounds followed one after another, we've launched the Codeforces::Gym project, we've added numerous improvements/fixes/innovations. Here's a short list of our deeds:
<img src="http://assets.codeforces.com/2012/2012-codeforces-google-trends-en.png" style="float:right;margin:0 1em 1em 1em;"/>
- when a user votes for a post/comment, his/her authority is taken into consideration, we've introduced anti-bot and froud-detection heuristics
- the Codeforces::Gym has been opened and has come through many improvements
- the Codeforces Markup, based on Markdown has been introduced, accompanied with special Codeforces tags
- Codeforces helped VK.com to carry out a amplitudinous VK Cup 2012 championship which had around 6000 participants!
- the CROC company has used the...
62.
CF-Predictor news Hello all!
I have some news to share about CF-Predictor (a service that allows you to view rating changes before official results). This extension [was launched](https://codeforces.me/blog/entry/50411) almost 6 years ago. Number of users has grwon from a couple hundreds to nearly 50k! I'm very proud that this service is used by so many people!
One of the cool features of mine extension is that it is friendly to codeforces API :) All the request to codeforces are sent from just one backend server. Therefore, users don't overload codeforces with extra API calls.
I was using Heroku as a cloud provider to run my servers. Unfortunately, they are closing their free accounts on Nov 28th. So, I decided to take down my servers on heroku. Thus, starting from 2022-11-27 [cf-predictor-frontend.herokuapp.com](https://cf-predictor-frontend.herokuapp.com) and [cf-predictor.herokuapp.com](https://cf-predictor.herokuapp.com) will **not** work.
On a bright side, I though that upsetting 50k ...
63.
Updating Trainings <img src="http://assets.codeforces.com/images/wizard-girl-en.jpg" style="float:right;margin:1em;width:300px;"/>
Good evening!
I'm glad to announce a series of improvements in the Codeforces::Gym subproject. Many people faced the following problem as they prepared problems in this section: to add a problem or edit an existing training a little bit, one had to parse and repackage the whole contest from the scratch in the Wizard. Another variant was manually editing the files on FTP. Both these ways added unreasonable challenges.
From now on you can create contest patches in the Wizard. Want to add a problem? There's no need to repackage the whole contest. Update the standings, add resources or statements? The procedure is simplicity itself. All you've got to do is to run the Wizard in the update mode and add only the really necessary changes. The Wizard will assemble the contest.zip package and mark it as a patch. You can upload the package into Taskbook in the usual manner.
...
64.
About the programming languages **This post is no longer relevant; it has become significantly outdated. You should read the post at [https://codeforces.me/blog/entry/121114](https://codeforces.me/blog/entry/121114)**.
<p> Later you'll be introduced to the rules of the Codeforces contests, which differ from those of <a
href="http://en.wikipedia.org/wiki/ACM-ICPC#Contest_rules">ACM-ICPC</a>, TopCoder, GCJ, and I hope they'll bring
some difference to the world of programming competitions. Most of the official competitions will be carried out
according to these rules, though there will be more traditional contests. For example, Codeforces Beta Round #1 will
be carried out according to the familiar <a href="http://en.wikipedia.org/wiki/ACM-ICPC#Contest_rules">ACM-ICPC</a>
rules. For some time testing will be based on Windows, but things might change in future, fortunately, the system
supports testing on different platforms, even within one contest. </p>
<p> At the present time the ...
65.
Getting ready for ACM-ICPC: weekly trainings on Codeforces <img src="http://worker.codeforces.ru/static/images/icpc/icpc_logo.png" style="float:right;margin:0.5em 1em 1em 1em;"/>
The new season of a collegiate team championship ACM-ICPC is about to start. For example, the registration for the Southern (Saratov) Subregional Contest is already running. I am sure that many participants of the Codeforces rounds will take part in ACM-ICPC this year.
We are launching a series of weekly practice trainings on Codeforces. Naturally, they will be held within Codeforces::Gym. Feel free to participate!
The practice starts at about 12:10 PM (UTC), which is 16:10 Moscow Time. We are going to practice using the problems of different contests of the past years. All you need is common sense and observing these simple rules:
- We will not publish the problem source before the practice starts. We want you to solve the problems on your own in a fair competition. If you use somebody else’s code or cheat in any other way, you will be disqualified. If y...
66.
UNSW Battlecode - $20,000+ AUD in prizes, starting 21 September Hello, Codeforces!
We're excited to invite you to **[UNSW Battlecode](https://battlecode.au/)**, a 4-week bot-programming competition sponsored by **Jump Trading and HRT**.
In teams of **up to 4**, you can implement procedural (rule-based algorithms allowed, ML allowed) decision-making logic for autonomous bots in a grid-based, turn-based strategy game. Your submissions will compete against other teams in **1v1 matches**.
There are **$20,000+ AUD in prizes**, alongside exclusive recruiting opportunities with our sponsors. The competition starts on **21 September**, and **registration is open now!**
## Competition format
Unlike a normal CF contest, the objective is to develop a strategy that performs well against other submissions (you can think of it as a PvP heuristic contest). The competition combines algorithm design, adversarial decision-making, and iterative optimisation — implement a strategy, evaluate its behaviour in matches, identify failure cases, and ref...
released at launch. Throughout the competition, you can: - **Test and debug**
through our local and, The full game rules and starter kit will be released at launch. Throughout the
competition, you can:
67.
ICPC Amritapuri Practice Session #3 Hello Codeforces,
I invite you to participate in the **ICPC Amritapuri Practice Session #3** hosted on **CodeDrills** in coordination with **ICPC Amritapuri**. It would be a **1.5 hours** long contest having **4 problems** of varying difficulty.
**Contest Details**
- Contest Link — https://codedrills.io/contests/amrita-icpc-practice-session-3
- Date — **14 Feb 2021**, Sunday
- Start Time — **[20:30 IST](https://www.timeanddate.com/worldclock/fixedtime.html?msg=ICPC+Amrita+Practice+Session+%233&iso=20210214T2030&p1=438&ah=1&am=30)**
- Duration — **1.5 Hours**
- Will follow standard ICPC scoring system (20 minutes penalty and 1 point per problem)
**Registration**
You will need an account on [CodeDrills](http://codedrills.io/) to participate in the contest. If you have not signed up on CodeDrills yet, do so [here](https://codedrills.io/login). If you already have an ac...
68.
OpenFrontierCS Challenge: the AHC for Human-AI agent Collaboration on Open-Ended Tasks **Hello Codeforces!**
Today, our team (me, [user:JoyeMang,2026-07-10], [user:Tohsaka_Sakura,2026-07-10], along with other amazing collaborators), with the support from Eigen Labs, are officially launching the **FrontierCS** AutoResearch challenge which is live at [http://openfrontiercs.com](http://openfrontiercs.com)!
[Simply link your GitHub account and join!](http://openfrontiercs.com)
Think of this as an **AtCoder Heuristic Contest where AI agents are fully allowed and actively encouraged and the duration is much longer for space to fully optimize.**
**The Goal: Pushing the Ceiling of Human-Machine Collaboration**
We want to measure the limits of human-AI collaboration on complex, ICPC challenge-style problems. While the open-source AI community is already heavily involved, we believe **human intelligence from competitive programmers is the missing key**. We want to see **how top algorithmic minds can guide, improve, and integrate their problem-solving wisdom into the...
69.
Kotlin Heroes Announcement <img src="/predownloaded/d3/f6/d3f67b5afe94939d82d9358aeb7a0edcf6a8d33f.png" style="width:300px;float:right;margin:0 1em 1em 1em;"/>
Hello, Codeforces!
We are happy to announce that in partnership with Codeforces to promote [Kotlin programming language](https://kotlinlang.org/) we are launching a series of "Kotlin Heroes" programming contests.
Kotlin programming language was introduced by JetBrains in 2011 and reached its first stable version 1.0 in 2016. The current language version is 1.3.31. The language is focused on solving the needs of application developers in various domains. Kotlin is a statically typed language that is designed for writing concise code, with less ceremony and more substance in it, and to scale from applications of just a few lines long to multi-million-lines projects.
While not being specifically designed for competitive programming, it incidentally fits well in this domain, reducing the typical amount boilerplate that a programmer needs to write...
Announcement of Kotlin Heroes: Episode 1
70.
Ten years of competitive programming 3 Hey Codeforces!
I’m AmirReza PourAkhavan, the former Codeforces Contest Coordinator. I let the story become complete and I’m sharing it now.
The story is about a 16-year competitive programmer, who left his family and migrated to another city alone to follow competitive programming. After seven years, he advanced to the International Collegiate Programming Contest World Finals, twice.
Read the previous post [here](https://codeforces.me/blog/entry/108838).
**Read the Persian version** [**here**](https://docs.google.com/document/d/e/2PACX-1vSUoFC9tLgDCji6rSCYy-RYoUG1_6uOQnHz_LlLKe6KksWBYWO4r6clDly5YxIgzu1g3Tj31weDxgWz/pub).
What happened previously
===
I was a lone programmer, in a small city, trying to learn CP and prepare for the Iran national olympiad. It was not as successful as I expected. I tried to change my school and I migrated to Tehran, alone. I entered AE high school to learn from its inspiring teachers.
11th grade
===
First day of school. I got to ...
spread cocoa on bread and make breakfast. The school served lunch. The
remaining:launch for two days
71.
Codeforces Round #120 (Div.2) — editorial #### $A$ --- [Vasya and the Bus](http://codeforces.me/contest/190/problem/A)
Firstly, if $n=0$, then children can't be in the bus, so if $m=0$ then the answer is $(0, 0)$, otherwise the answer is $"Impossible"$.
Now $n>0$. If $m==0$, than it is only one possible variant of passage --- the answer is $(n, n)$.
Otherwise, more grown-up take some children, less the sum that people pay. So, if only one adult takes all children, than we get maximal sum --- $n+m-1$. Maximum $min(n, m)$ adults can take the children with them, so the minimal answer is $n+m-min(n, m)=max(n, m)$.
#### $B$ --- [Surrounded](http://codeforces.me/contest/190/problem/B)
Let's find the minimum distance between two circles $L$. Then the answer to our problem is $L/2$.
Now $d$ is the distance between the centers of the circles, $R$, $r$ --- their radiuses. There are 3 possible cases:
- Circles don't intersect. Then $L = d - R - r$. Firstly, it's reachable: let's consider the segment, connecting the ce...
$. Then we print $","$ and launch $gettype(j)$ (it returns $k$), then we print
$">"$ and return $k
Tutorial of Codeforces Round 120 (Div. 2)
72.
Fabby — приложение для обработки изображений с помощью нейросетей от олимпиадников Слышали про запуск приложения по обработке изображений [Fabby](https://itunes.apple.com/by/app/fabby-photo-picture-editor/id1147967413?mt=8) (iOS)? Там не обошлось без рук олимпиадников!
Нейросети обрабатывают изображения на самом девайсе. [По словам команды](https://roem.ru/08-12-2016/237844/fabby-launch/), у них это сделать будет проще, чем в Prisma или MSQRD, которые тоже позволяют редактировать снимки.
<iframe src="//vk.com/video_ext.php?oid=3240642&id=456239038&hash=d7afc62fc5a8d522&hd=2" width="853" height="480" frameborder="0" allowfullscreen></iframe>
Людям нравится — Юрий [user:Ra16bit,2016-12-09] Писарчик, член команды Fabby, пишет на страничке Вконтакте:
<center><img src="http://codeforces.me/predownloaded/b7/88/b788ab607295d0dce2d56efd7f3bada1132915e9.png"></center>
Почитайте, что он рассказал мне о проекте:
— _Поздравляю с запуском! Видео с котиками очень крутое. Жду выхода приложения на андроид. Теперь не надо будет вырезать себя в фотошопе...
/237844/fabby-launch/), у них это сделать будет проще, чем в Prisma или MSQRD,
которые тоже
73.
Graph Theory COPS Youtube Channel [HINDI + ENGLISH] Hello, Codeforces community
The Club of Programmers, IIT BHU is excited to announce the launch of Graph Theory playlist of COPS YouTube channel.
The playlist contains some basic and intermediate concepts of graph theory. The videos and the corresponding document not only provide explanation to the concept but also provide a proper roadmap on how to study these concepts along with the practice problems.
**The videos are in a mix of Hindi and English.**
Graph Theory Playlist link : [https://www.youtube.com/playlist?list=PLLt4yMoVgczV8N1LTzA6eXoWlXU9MTQv7](https://www.youtube.com/playlist?list=PLLt4yMoVgczV8N1LTzA6eXoWlXU9MTQv7)
Following topics are covered in the playlist:
- [Basic graph theory (Terminologies, dfs and bfs)](https://www.youtube.com/watch?v=egUxXxnASDU&list=PLLt4yMoVgczV8N1LTzA6eXoWlXU9MTQv7&index=1)
- [Dijkstra algorithm: Single source shortest path algorithm](https://www.youtube.com/watch?v=3lap9xe7RSQ&list=PLLt4yMoVgczV8N1LTzA6eXoWlXU9MTQv7&index=3&...
Hello, Codeforces community The Club of Programmers, IIT BHU is excited to
announce thelaunch, The Club of Programmers, IIT BHU is excited to announce the launch of Graph
Theory playlist of COPS
74.
Codeforces Round #188 (analysis) Problem analysis v 0.9.
[problem:318A]
In this problem we need to understand how exactly numbers from $1$ to $n$ rearrange when we write firstly all odd numbers and after them all even numbers. To find out which number stands at position $k$ one needs to find the position where even numbers start and output either the position of the odd number from the first half of the sequence or for the even number from the second half of the sequence.
[problem:318B]
In the heavy metal problem one needs to find the number of the substrings in the string S with a given prefix A and given suffix B.
If we mark black all the starting positions of the entries of the string A in S, and white all the starting positions of the entries of the string B, then we come to the following problem: count the number of pairs <black position, white position> (in this order).
To solve this it is enough to iterate from left to right counting the number of the passed black positions. Meeting black position...
those steps one needs to launch emulation. If $x > 0$ and $y > 0$, then pair
"grows exponentionaly, . To count precise number of those steps one needs to launch emulation. If $x >
0$ and $y > 0$, then
75.
Codeforces Round 1132 (Div. 2) Editorial #### [problem:2284A1]
<spoiler summary="Hint">
It is sufficient to apply operations to only two points.
</spoiler>
<spoiler summary="Solution">
Let us prove that the maximum area is achieved if we shift one of the points by $\lfloor \frac{n}{2} \rfloor$ steps up, and the other by $\lceil \frac{n}{2} \rceil$ steps to the right. To do this, consider the bounding rectangle of the resulting triangle after all point shifts; let its side lengths be $a$ and $b$, respectively. We will show that its maximum area is precisely $\frac{ab}{2}$. Since triangle $ABC$ is inscribed in our rectangle, at least one of its vertices must coincide with a vertex of the rectangle. Without loss of generality, let this be vertex $A$. If we denote the angles adjacent to it by $\alpha$ and $\beta$, it can be shown that the maximum area is achieved when the value $\tan \alpha \cdot \tan \beta$ is minimized, which means it is equal to $0$ for $0 \le \alpha + \beta < \frac{\pi}{2}$.
76.
My Course at Harbour.Space University: Advanced Algorithms and Data Structures (January, 2019) <img src="/predownloaded/c0/52/c052c92fc998292e9705f9924413b581d13515ba.jpg" style="float:right; margin: 0 1em;"/>
Hi, Codeforces!
I am glad to announce and invite you to the second launch of my course on algorithms and data structures.
On 7-25 of January, 2019, I will be giving the course <a href="https://goo.gl/u5nTmk">"Advanced Algorithms and Data Structures"</a> at <a href="https://goo.gl/zDSsaQ">Harbour.Space University (Barcelona, Spain)</a>. It will be in English, and is not limited to Harbour.Space students — anyone is welcome! Who wants to join?
This course isn't just for Harbour.Space students, it is also open to Codeforces participants, who will be offered a special price, 1000 EUR. The cost does not include travel or accommodation.
<br/>
<center style="margin:20px;">
<a style="font-size: 24px; padding: 8px 14px; background-color: #673AB7; color: white;" href="https://goo.gl/u5nTmk">Register for the Course →</a>
</center>
The curriculum will i...
I am glad to announce and invite you to the second launch of my course on
algorithms and data
77.
[Tutorial] Setting up Windows C++ environment — Microsoft edition Hello. This is kind of continuation of this post https://codeforces.me/blog/entry/102287. In this tutorial I'll try to explain how to write and compile C++ code on Windows, using tools provided by (mostly) Microsoft. I'm going to use latest versions.
Terminal
========
First of all, let's install [Windows Terminal](https://www.microsoft.com/store/productId/9N0DX20HK701) and [MS PowerShell](https://www.microsoft.com/store/productId/9MZ1SNWT0N5D). Standart windows command line is just not usable. Let's also install [winget](https://www.microsoft.com/store/productId/9NBLGGH4NNS1) — this is a package manager similar to, for example, homebrew. Maybe chocolatey is better but, again, this one is developed by Microsoft.
Of course Microsoft Store isn't mandatory, you can use any other source for these packages.
I'd also suggest to try [starship](https://starship.rs/) command prompt — very useful tool, supports powershell as well.
Compilers and tools
================...
so you'll be able to launch it from console by typing `subl`. Run ~~~~~
rundll32 sysdm.cpl, Add sublime text installation folder to your PATH so you'll be able to launch
it from console by
78.
Codeforces Round #130 (Div. 2) Tutorial First, arrange the problems in order of their difficulties. The authors assume such order: A, D, B, C, E. Now make the tutorial of problems in their order in the contest.
[problem:208A]
This problem was technical. First, you should erase all occurrences or word WUB in the beginning and in the end of the string. And then parse the remaining string separating tokens by word WUB. Empty tokens should be also erased. Given string was rather small, you can realize the algorithm in any way.
[problem:208B]
In this problem you could write breadth-first search. The state is the following four elements: number of remaining piles and three strings --- three rightmost cards on the top of three rightmost piles. We have two transitions in general case. We can take the rightmost pile and shift it left by $1$ or $3$ on another pile. If the number of remaining piles become $0$ at some moment print $YES$, else print $NO$. The number of states is $O(N^4)$, the number of transitions $2$, so the...
some set of rooted down- oriented trees. First, launch depth-first search from
every root of every, In this problem you have some set of rooted down- oriented trees. First, launch
depth-first search
79.
Code League — National Competitive Programming Contest — Round 2 — Editorial Here is the link to the contest: [Link](https://codeforces.me/contestInvitation/f528fcc29732183e36f82a0adfdc6dbac0743f3f)
### [A. Free Coupon](https://codeforces.me/gym/690685/problem/A)
<spoiler summary="Rate the Problem">
- **How good is this problem?**
- Very Good
- Good
- Bad
- Very Bad
- **How hard is this problem?**
- Very Easy
- Easy
- Hard
- Very Hard
</spoiler>
<spoiler summary="Hint">
Which items should be taken using coupons?
<spoiler summary="Answer">
Since a coupon can be used on any item regardless of its price, it is always best to use coupons on the most expensive items. This allows us to spend our coins only on cheaper items.
</spoiler>
</spoiler>
<spoiler summary="Solution">
The problem asks us to find the maximum number of items Abenezer can obtain given $k$ coins, with the offer that every $b$ items bought with coins yiel...
80.
Educational Codeforces Round 146 [Rated for Div. 2] Hello Codeforces!
On [contest_time:1814] [contest:1814] will start.
Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="http://mirror.codeforces.com/blog/entry/51208">blog post</a>.
This round will be **rated for the participants with rating lower than 2100**. It will be held on extended ICPC rules. The penalty for each incorrect submission until the submission with a full solution is 10 minutes. After the end of the contest, you will have 12 hours to hack any solution you want. You will have access to copy any solution and test it locally.
You will be given **6 or 7 problems** and **2 hours** to solve them.
The problems were invented and prepared by Adilbek [user:adedalic,2023-04-05] Dalabaev, Ivan [user:BledDest,2023-04-05] Androsov, Maksim [user:Neon,2023-04-05] Mesche...
&utm_campaign=bcn_b2c_cyber_security_re-launch) to learn from the best in the
field and take your, &utm_medium=partner&utm_campaign=bcn_b2c_cyber_security_re-launch"
style="text-decoration:none; font, &utm_medium=partner&utm_campaign=bcn_b2c_cyber_security_re-launch), чтобы
учиться у лучших в этой области и, =codeforces&utm_medium=partner&utm_campaign=bcn_b2c_cyber_security_re-launch"
style="text-decoration:none, _We are looking for talented individuals who want to launch their careers in
**Cyber Security, launch their careers in **Cyber Security** with a **50% scholarship to study in
Barcelona**._ _If
Announcement of Educational Codeforces Round 146 (Rated for Div. 2)
81.
C++ and VSCode setup on macOS ### Problem to be addressed
On Linux it is pretty straightforward to set up the debugger for C++ on VSCode. The workflow is:
- Write your code
- Go to the [Run and Debug] VSCode section
- Click on run active file or something similar
- Debug your code
On macOS you will run into a lot of silly problems, such as:
- Can't find `#include<bits/stdc++.h>`
- Installed g++ and got the debugger running, buck can't write input to `std::cin` in the integrated terminal, because it says
~~~~~
Build finished successfully.
* Terminal will be reused by tasks, press any key to close it.
~~~~~
and then closes the terminal, making it impossible to write to `std::cin`.
After some time browsing the internet I found the solution for all those problems and got my setup working just like on linux.
### Solution
Let's brake the solution step by step, from a almost brand new macOS.
1. [Install Homebrew](https://brew.sh)
2. Install g++ (`brew install gcc`)
3. Down...
": "lldb", "request": "launch", "name": "Debug C++", "program, ": [ { "type": "lldb", "request": "launch", "name": "Debug C
82.
Editorial for Codeforces Round #346 (Div. 2) [659A — Round House](http://codeforces.me/contest/659/problem/A)
The answer for the problem is calculated with a formula $((a - 1 + b)$ $\mod$ $n$ + $n$) $\mod$ $n$ + $1$.
Such solution has complexity $O(1)$.
There is also a solution with iterations, modelling every of $|b|$'s Vasya's moves by one entrance one by one in desired direction, allowed to pass all the tests.
This solution's complexity is $O(|b|)$.
[659B — Qualifying Contest](http://codeforces.me/contest/659/problem/B)
Let's consider the participants from every region separately. So for every region we just need to sort all of its participants by their score in non-increasing order. The answer for a region is inconsistent if and only if the score of the second and the third participant in this order are equal, otherwise the answer is the first and the second participant in this order.
The solution complexity is $O(n \log{n})$.
[659C — Tanya and Toys](http://codeforces.me/contest/65...
least one cycle. Let's take arbitrary vertex from any of the cycles and launch
a DFS (as above) from, vertex from any of the cycles and launch a DFS (as above) from it. All
vertices except chosen will be
Tutorial of Codeforces Round 346 (Div. 2)
83.
Topcoder из Eclipse (инструкция для новичков) Этот текст я пишу в основном для ребят младших курсов своего университета, чтобы они наконец начали участвовать в соревнованиях Topcoder. Так получилось, что на Codeforces это сделать мне наиболее удобно. Может быть, кому-то еще пригодится.
### Что вообще такое Topcoder
[Topcoder](http://community.topcoder.com/tc) — это как Codeforces, только менее удобный. На самом деле, помимо соревнований по спортивному программированию там проводится еще куча мероприятий, которым аналогов в мире нет, так что многим деваться просто некуда :) А для тех, кто занимается именно спортивным программированием, это просто еще три-четыре неплохих контеста в месяц.
Если кликнуть на сайте на ссылку Events, а далее — Event Calendar, можно увидеть [расписание](http://community.topcoder.com/tc?module=Static&d1=calendar&d2=thisMonth) этих контестов. Время там указано какое-то американское, чтобы получить московское, нужно в разное время года прибавлять либо 8 часов, либо 9. Кроме того, можно к...
Competitions — Algorithm — Single Round Matches — Launch Arena. Это
Java-апплет, в котором, на сайт и искать там ссылку Launch Arena — все делается из IDE., — Algorithm — Single Round Matches — Launch Arena. Это Java-апплет, в котором
вы типа
84.
OI Checklist: update blog (tons of new features), call for suggestions # OI Checklist – Two Weeks of New Features!
It’s been about two weeks since I first announced [OI Checklist](https://checklist.spoi.org.in) in [this blog post](https://codeforces.me/blog/entry/145434). The blog was very well received, and I’d like to thank you all for that! In fact, since launch OI Checklist has already grown to 2,261 problems across 18 olympiads and is being used by 214 users. (If you haven’t tried it yet, you can check out the [demo mode](https://checklist.spoi.org.in/demo) to see how it works without signing up.)
Over these two weeks, I’ve been working on OI Checklist and added a lot of new features: some functional, some UI/UX improvements, and some smaller tweaks. Here’s a summary of the most important ones:
---
## qoj.ac Sync — Fully Supported
### Full Checklist
That’s right! You can now sync with **both oj.uz and qoj.ac**.
|  |  |
|-------------------------------...
like to thank you all for that! In fact, since launch OI Checklist has already
grown to 2,261, launch OI Checklist has already grown to 2,261 problems across 18 olympiads and
is being used by 214
85.
Call for Contest Admin / Problemsetter! We are looking for **contest admins** and **problem setters** for a contest series we are starting at TheJobOverflow. We are experimenting with the format and variety of problems — the contests are primarily geared toward algorithms/ideas with a lesser component of peeling multilayer observations. TJO has 6,000 users and has evaluated 10,000 solution to programming tasks this week.
What is TJO? TheJobOverflow is an **Open Community Platform** for interview preparation & CP. It's built and managed by alumni of IIIT Hyderabad, IIT Bombay, IIT BHU, and IIT Guwahati. Team has ICPC world finalists, IOI medalists, Math olympiad folks and also houses key people who authored math-contest [Gordian Knot](https://codeforces.me/blog/entry/57311) a few years ago ( :
Our contest series is yet to be launched, meanwhile we have compiled & tested [**350 problem's Question Bank**](https://thejoboverflow.com/problems/) which includes **latest Coding Round & Interview** problems asked by **Go...
86.
Codeforces Round #219 editorial Sorry for late.
This is the editorial of Codeforces Round #219. Div2 A, Div2 B, Div1 C are made by [user:m.kagamiz,2013-12-15], and other problems are made by me.
[problem:373A] /\\_/\
First, you need to count the occurence of each number (1 through 9).
If none of them are greater than 2 * k, Cucumber boy is able to press
the panels in perfect timing.
Complexity is O(1).
My solution : http://ideone.com/CwQtBv
[problem:373B] /\\_/\
Naive simulation (subtracting S(i) * k from w while w >= 0) won't finish in 2 seconds.
At first, these two facts will make it easier to solve the problem :
1. k doesn't matter for solving this problem, so you can simply divide w with k at the first point.
2. S(10^x) + S(10^x + 1) + ... + S(10^(x+1) — 1) = 9 * x * 10^x .
There are many ways to solve this problem, and I'll show you 2 ways.
1. Binary Search
Let's define f(n) as \sum_{k=1}^{n} S(n). This problem can be solved by finding largest
x that satisfies f(x) &md...
Tutorial of Codeforces Round 219 (Div. 2)
87.
Important Update: Second Qualification Round for MACSO is Now Live! Dear MACSO Participants,
We are excited to launch the **Second Qualification Round**, which is now live and runs from September 1 to October 1. This round introduces new challenges and opportunities for all participants.
What You Need to Know:
**3 New Problems Added**: The second qualification round introduces 3 new problems. Points from the original 3 problems (A, B, and C) **still count** toward your total score. Scores will be **combined** from both rounds, and time will no longer be a tie-breaker. The new problems will become progressively harder, so aim to score as many points as possible on each one.
**Separate Rankings for Finals**: Participants aiming for the In-Person High School Finals at Brookline Teen Center, MA, will be ranked separately from those competing for the Online Open Finals.
**Resubmit Your Solutions**: We have set up a new Codeforces competition. If you are a high schooler planning to participate in the in-person finals, you must resubmit your so...
Dear MACSO Participants, We are excited to launch the **Second Qualification
Round**, which is, We are excited to launch the **Second Qualification Round**, which is now live
and runs from
88.
Yet Another Blog On CP Setup ## Is It Worth Reading This Blog?
The aim of this blog is simply to show my setup and give a brief preview of how it’s done.
## [TL;DR]
This is my [repo](https://github.com/ThePino/cp) with my basic setup.
You can try it out in two ways:
1. By clicking the **"Open in GitHub Codespaces"** button in the README.
2. By cloning the repository and opening the folder in a dev container.
## Why
As the title suggests, this is another blog about a setup for competitive programming.
For several reasons, I often find myself using a machine that doesn’t have the basic tools for competitive programming, such as `g++` and `python3`. Every time, I get frustrated having to install everything from scratch and configure it the way I like.
To solve this problem, I decided once and for all to set everything up properly and reuse the entire setup every time I need it.
### How Did I Do It?
To achieve this goal, I used the following technologies:
* [Docker](https://www.d...
contest, I haven’t noticed any slowdown while programming. You can also launch
it via GitHub, You can also launch it via GitHub Codespaces, so you don’t even need to install
Docker or other
89.
Codeforces Beta Round 76 - Analysis <p>At first I tell about the contest at all.<br></p>My problems in the contest were A-div2, B-div2, C-div2/A-div1, E-div2/C-div1, D-div1. I wanted to make only div.2 round, but then we decided to give you seven problems at both divisions. <a class="rated-user user-admin" href="../../../profile/MikeMirzayanov" title="Штаб, MikeMirzayanov">MikeMirzayanov</a> prepared the problem about milk pouring and <a class="rated-user user-orange" href="../../../profile/anonymous" title="Майор anonymous">anonymous</a> gave E-div1 problem. Also <a class="rated-user user-admin" href="../../../profile/RAD" title="Штаб, RAD">RAD</a> gave some advices to complicate problems Azembler and Flags a bit.<br><p>And now let's start analysis.<br><br><br><b>Problem A (div.2) - Restoring Password</b><br><br>Password was very easy to restore. You should just iterate over groups of 10 characters in the first string and over all codes. Then, if some number's code is equal to the group - print t...
order (it works faster), but 5 seconds is such TLE that you can solve it any
way. Or you canlaunch
Tutorial of Codeforces Beta Round 76 (Div. 2 Only)
90.
Mathforces In [my previous blog](https://codeforces.me/blog/entry/154318), I mentioned we probably (with hope) end with platforms like Mathforces. Not long after the blog, a guy shared [SolveFire](https://www.solvefire.net/dashboard) with me that is basically "Codeforces, but for math".
So today, I want to introduce this "Mathforces" and here it is:
The UI is super clean and modern. It obviously has both light and dark modes, which you can toggle by clicking the little "orz" guy in the top right next to your notifications. Did I really need to mention that? Yes, because orz.
Like any good Mathforces, it revolves around contests. Looking at the archives, the oldest contest dates back to February, so the platform probably launched in late 2025 or early 2026. They host weekly rounds featuring Bronze, Silver, and Gold divisions, and sometimes even Platinum and Diamond.
You can create your own community contests, a...
91.
The Dramatic Collapse of Terra Luna: Could the same happen to NEAR? ## Background
Recently, it [was announced](https://codeforces.me/blog/entry/101398) by [user:MikeMirzayanov,2022-06-03] that NEAR would be contributing to the funding of Codeforces. Clearly, the influx of additional funding was very important to Codeforces. In this blog I want to look at the [NEAR cryptocurrency](https://near.org/) in more detail, and analyze the possibility of a complete collapse.
## The Story of Terra Luna
Between May 5 and May 12th, the cryptocurrency Terra Luna lost **all** of it's value: wiping _$45 billion_ off of the crypto market.
What were the "fundamental design mistakes" (according to the Binance CEO) of Terra Luna? Perhaps simply the entire idea of an **algorithmic stable coin**.
A "stable coin" is merely a cryptocurrency whose value is supposed to remain fixed, usually relative to the dollar. For example, the [stable coin USDC](https://www.coindesk.com/price/usd-coin/) has had a maximum pric...
92.
Codeforces Round 959 sponsored by NEAR (Div. 1 + Div. 2) Hello, Codeforces!
I am pleased to invite you to participate in [contest:1994], which will be held at [contest_time:1994]. You will be given **8 problems** and **2 hours** to solve them. It will be rated for **all participants**.
The theme of the round is computer games!
Tasks for the round were prepared by [user:EJIC_B_KEDAX,2024-07-16], [user:zwezdinv,2024-07-16], [user:green_gold_dog,2024-07-16], [user:molney,2024-07-16], [user:azureglow,2024-07-16] and [user:Sokol080808,2024-07-16].
We would like to thank everyone who assisted in the preparation of this round:
1. Our coordinator [user:74TrAkToR,2024-07-16] for his useful advices and help in preparing the tasks!
2. [user:Qwerty1232,2024-07-16] for red interest in testing the round.
3. [user:turmax,2024-07-16] for the red-black testing.
4. [user:makrav,2024-07-16], [user:arbuzick,2024-07-16], [user:Anonymous_Noob,2024-07-16], [user:Hyperbolic,2024-07-16] for red testing.
5. [user:ivan.alexeev,2024-07-17], [...
Announcement of Codeforces Round 959 sponsored by NEAR (Div. 1 + Div. 2)
93.
Group Classes at Algoritmi Academy Hello again, Codeforces Community,
We are back and thrilled to announce the official launch of our group classes! Following your valuable feedback from [our first announcement](https://codeforces.me/blog/entry/124820), we've defined our rules for group classes.
We're excited to offer a special price on group classes! Check out these fantastic rates:
- 2-student class: **$19** per session
- 3-student class: **$15** per session
Here's the best part: our unique group class program allows for individual registration. **Sign up on your own**, and we'll begin your sessions **at the group rate**, continuing with one-on-one classes **until we find suitable classmates** to join you. This means you start benefiting from the group rate immediately!
For more details and to take advantage of this limited-time offer, please visit [our website](https://algoritmiacademy.github.io) (registration takes just 2 minutes!).
For quick registration, just fill out [this form](https://docs.g...
Hello again, Codeforces Community, We are back and thrilled to announce the
officiallaunch of, We are back and thrilled to announce the official launch of our group classes!
Following your
94.
CFCoach: A Chrome Extension to Practice Smarter on Codeforces and Profile-Based Training Hi everyone,
I built CFCoach, a Chrome extension for Codeforces users who want structured practice directly inside Codeforces.
Chrome Web Store: [https://chromewebstore.google.com/detail/ackkplclopoecipnfllalmencpbnonoo?utm_source=item-share-cb](https://chromewebstore.google.com/detail/ackkplclopoecipnfllalmencpbnonoo?utm_source=item-share-cb)
Website: [https://cp-coach-ebon.vercel.app](https://cp-coach-ebon.vercel.app)
### Why CFCoach?
Most users face three common issues:
1. Choosing daily problems takes too much time.
2. Weak areas are hard to identify clearly.
3. Practicing under contest pressure with friends needs manual setup.
CFCoach solves this with:
1. Profile Analysis
2. Daily Mix (regular structured practice)
3. Contest Generator (time-bound mashup practice with friends or competition)
### What each feature does?
#### 1. Profile Analysis
Profile Analysis helps you understand:
1. Your stronger and weaker topic areas
2. Difficulty ranges whe...
1. Open a Codeforces profile and launch CFCoach. 2. Review Profile Analysis to
identify focus, ### Real usage flow 1. Open a Codeforces profile and launch CFCoach. 2. Review
Profile Analysis
95.
Code, Compile and Run — An integrated development environment for the web on CodeChef I invite you all to use the newly launched [web IDE](http://codechef.com/ide) on CodeChef. It has some cool features:
- An advanced code editor along with syntax highlighting. Love ‘vi’ or ‘emacs’? You will love this as well.
- Autocompletion of code (It isn’t great for the new programmers out there, so for them an option to disable it in settings menu is present.)
- Execution for all the languages available on CodeChef (50+)
- More than 30 themes to choose from.
- Drag and drop a file and start editing. And download your code back in a file once you are done.
- Feel distracted with so many things on the browser? The full screen feature for you.
- Love saving your code templates? Do not need to carry it anywhere. Do it on the ide and that too a different one for each language.
- Well, last but not the least. Love keyboard shortcuts ? We have an surprise for you in settings menu.
Apart from these, one of the most important issue that we hope this will solve is the unintend...
96.
What happened to 1400+ Codeforces users from 2021 to now? I took every Codeforces user who (a) was rated **1400 or higher at some point in 2021** and (b) is **still competing** (active rated list, and at least one rated contest since 2025-01-01). That is **746 users**. I pulled their full rating histories from the public Codeforces API and measured the cohort at each major AI release that mattered for competitive programming.
All numbers below come from `user.ratedList` and `user.rating`. Data was fetched on 2026-10-08. Charts and code are available on request.
**Important caveat up front:** this post shows *what happened*. It does not show *why*. Rating trends have many causes, and I mark clearly where I'm speculating.
## How the cohort was built
1. `user.ratedList?activeOnly=true` returned 43,131 active rated users.
2. I kept those registered by the end of 2021 whose max rating is ≥ 1400: **1,600** candidates.
3. For each candidate I fetched `user.rating` and kept those whose rating was ≥ 1400 at any time in 2021 (including th...
announcement) | | 2022-11-30 | ChatGPT launch | | 2023-03-14 | GPT-4 | |
2024-05-13 | GPT-4o
97.
Beta Round #8 — csacademy.com Hello, Codeforces!
We are happy to announce that we're going to host a new contest at [csacademy.com](http://csacademy.com). Our [Beta Round #8](https://csacademy.com/contest/beta-round-8/) will take place on [Saturday, July/02/2016 16:00 (UTC)](http://www.timeanddate.com/worldclock/fixedtime.html?msg=CS+Academy+Beta+Round+%238&iso=20160702T16&p1=1440&ah=2). If you want to take part in this round you need to [register](https://csacademy.com/contest/beta-round-8/) before the contest begins. Just like the [previous rounds](https://csacademy.com/contests/), this will be a Div1 + Div2. Due to the feedback we've got during the past couple of weeks we decided to change the format, by adding an extra easy problem. So this round will consist of **7** tasks of varied difficulty.
#### Platform changes since Beta Round #7:
- We redesigned the homepage. It now includes a global chat, latest blog entries, future contests and top leaderboard.
- We launched a new lessons section:
1. [Intro...
98.
Invitation to CodeHurdle Athlos Contest — January 18, 2026 Hello Codeforces!
**First** and foremost, the entire **CodeHurdle** team wishes you a very **Happy New Year!**
As we step into 2026, we have been working tirelessly to evolve, grow stronger, and improve the quality of competitive programming for our community. To celebrate this new chapter, we are thrilled to announce the launch of our brand new contest series: **CodeHurdle Athlos.**
We invite you to participate in the inaugural round!
### Contest Details
* **Date:** Sunday, January 18, 2026
* **Time:** [contest_time:662818]
* **Duration:** 3 hours
* **Problem Count:** 8 Problems
* **Platform:** The contest runs on **Codeforces** (Gym/Mashup).
* **Registration:** **Mandatory** at [codehurdle.com](https://codehurdle.com).
The problem setting panel are: [user:amartya110,2026-01-14], [user:Lucifer_K,2026-01-14], [user:mahesh_9996,2026-01-14], [user:shivamp_07,2026-01-14], [user:Chetan_21,202...
announce the launch of our brand new contest series: **CodeHurdle Athlos.**
99.
10x Your CP Workflow: A Smooth Bash Script to Automate Parsing, Testing, Stressing and many more # 10x Your CP Workflow: A Smooth Bash Script to Automate Parsing, Testing, Stressing and many more
Hello Codeforces fam,
Over the past few months, I've been building and using a personal tool that **completely automates** my competitive programming workflow. From **parsing** problems to **checking solutions**, **stress testing**, **debugging**, and even **validating edge cases** — this tool has made my life 10x easier and smoother. And now, I’m excited to share it with you so that you can boost your productivity!
## What is this tool?
It’s a **template-driven Bash script** designed to integrate with [Competitive Companion](https://github.com/jmerle/competitive-companion) and streamline everything — whether you're solving problems on **Codeforces, AtCoder, LeetCode, CodeChef**, or anywhere else.
With just one command, you can:
- Parse problems
- Compile and run code
- Switch between fast and debug modes
- Stress test using a brute-force checker
- Validate solutio...
folder in VS Code:** code . This will launch Visual Studio Code in your
`codeforces` folder
100.
Let's face it, Polygon is horrible 
Polygon is not world's greatest evil. Polygon doesn't even have a particular defect that makes it horrible. You can't say what's exactly wrong with Polygon. Polygon seems to work, it seems like every feature is supported, but if you touch it here it will fall apart, and if you touch it there a problem (pun not intended) will appear. Or not, depending on your luck. Polygon is like PHP. For those who haven't read the famous rant, I'll cite it for you:
> I can't even say what's wrong with PHP, because-- okay. Imagine you have uh, a toolbox. A set of tools. Looks okay, standard stuff in there.
>
> You pull out a screwdriver, and you see it's one of those weird tri-headed things. Okay, well, that's not very useful to you, but you guess it comes in handy sometimes.
>
> You pull out the hammer, but to your dismay, it has the claw part on both sides. Still serviceable though, I mean, you can hit nails with the middle of the head holding it...
Script. You write commands to launch generators there, for example `gen_seq
9901 10000 1 100 > 5, somewhere. For this there is a so-called Script. You write commands to launch
generators there, for example
101.
List of IOI 2016 Participants <large><b>UPD:</b> a more complete and official list is now available <a href="http://stats.ioinformatics.org/contestants/2016">here</a>. I won't update this list anymore.</b></large>
Name | CF Handle | Country | Previous IOIs |
:----:|:---------:|:-------:|:-------------:|
[Román Castellarin](http://stats.ioinformatics.org/people/3173) | [user:ponysalvaje,2017-05-21] | [Argentina](http://stats.ioinformatics.org/countries/ARG) | 2013 — 2014 — 2015 |
[Maximiliano Redigonda](http://stats.ioinformatics.org/people/5519) | [user:asdf00001,2017-05-21] | [Argentina](http://stats.ioinformatics.org/countries/ARG) | 2015 |
[Gianni Weinand](http://stats.ioinformatics.org/people/5015) | [user:Weheineman,2017-05-21] | [Argentina](http://stats.ioinformatics.org/countries/ARG) | 2014 — 2015 |
Gastón Fontenla | [user:GastonFontenla,2017-07-12] | [Argentina](http://stats.ioinformatics.org/countries/ARG) | First Participation |
[Mushegh Shahinyan](http://stats.ioinformatics.o...
>
* The event date is August 12-19 ([Countdown
:D](http://www.timeanddate.com/countdown/launch?iso
102.
My new interview preparation website Hello, Codeforces
Here is something I've been working on for a while now. It's still in beta, but I think it's in a good shape to share. I think it's relevant to CF community, but if not, sorry for the spam :)
I am an ex-Google software engineer, and I wrote down almost everything I know about interview preparation, and launched a small website. It is something of a preparation course and guide at the same time.
Here is what's inside:
* 40+ articles about everything from resume to algorithms to compensation.
* Selected leetcode problems with hints, solutions and such.
* Code examples and explanations of common algorithms and techniques.
* A place where you can track your interview preparation progress.
Please take a look and let me know what you think. Hopefully, you will find it useful in your own preparation!
**Link**: [https://interviews.school/](https://interviews.school/)
P.S. I would appreciate any feedback. Feel free to point to any errors you will find. ...
103.
Looksery Cup Hello everybody!<br><br>
Our company wants to say thanks to Codeforces and congratulate it with the 5 years birthday:)<br><br>
A year and a half ago I and the team ([user:Sfairat,2015-01-01], [user:olpetOdessaONU,2015-03-03], [user:Sklyack,2015-03-03]) met Victor Shaburov and became co-founders of [Looksery](http://looksery.com). We work in Computer Vision and Augmented Reality areas.<br>
On behalf of all our collective I want to say thanks to
[user:MikeMirzayanov,2015-03-03] and Codeforces team, you do a great matter, and I'm sure it will have a huge impact on the IT segment of the nearest future. To tell the truth, I don't know how we would be able to solve the problems that we had at the beginning of Looksery path if there were no Codeforces or ACM ICPC in our lives.<br>
I would like to tell a few words about our organization, clarifying my opinion about popular [topic](http://codeforces.me/blog/entry/17302) of the last few days about competitive programming and "real" job.<br...
104.
Everything About Dynamic Programming **I decided to gather some good material on the web related to DP and found some good explanation by svg on topcoder forums..Hence wrote this blog.Will format it when i get time.**
**Problem:**
About 25% of all SRM problems have the "Dynamic Programming" category tag. The DP problems are popular among problemsetters because each DP problem is original in some sense and you have to think hard to invent the solution for it. Since dynamic programming is so popular, it is perhaps the most important method to master in algorithm competitions.
The easiest way to learn the DP principle is by examples. The current recipe contains a few DP examples, but unexperienced reader is advised to refer to other DP tutorials to make the understanding easier. You can find a lot of DP examples and explanations in an excellent tutorial Dynamic Programming: From novice to advanced by Dumitru. The purpose ...
easiest way to iterate through states in correct order is to launch DFS from
the root of tree. When DFS, layers into two halves and launch the same DP for each part recursively.
Choose final state as answer, ] ... DFS(0); //launch DFS from root = 0-th
105.
Using policy based data structure pb_ds on mac Are you facing issues compiling specific headers like `<ext/pb_ds/assoc_container.hpp>` and `<ext/pb_ds/tree_policy.hpp>` using the default compiler (clang) on your Mac?
I faced the same issue while solving [problem:1915F], where I wanted to use ordered_set.
Here's a step-by-step guide to switch to g++-13 and configure your IDE (in this case, VS Code) for successful compilation:
### Step 1: Install and Set Up g++-13
Install g++-13 (or latest version):
Open Terminal.
Use Homebrew to install g++-13: `brew install gcc@13`.
Verify Installation:
Type `g++-13 --version` in Terminal to ensure successful installation.
Update Terminal Configuration for g++-13:
Open the .bashrc or .bash_profile file in Terminal using a text editor like nano or vim: `nano ~/.bashrc` (or `nano ~/.bash_profile`).
Add the following line at the end of the file:
`export PATH=/usr/local/bin:$PATH`
Save the changes and apply ...
Open VS Code: Launch your Visual Studio Code editor.
106.
Eitri: A Practical Competitive Programming Workflow ## The problem [Eitri](https://github.com/veryshyjelly/eitri) solves
In competitive programming, the code you write while developing a solution often differs from the code you finally submit. During development, you benefit from a modular codebase: separate files for I/O utilities, graph algorithms, data structures, and other helpers make your work easier to read, test, and reuse. However, most online judges expect a single source file. Manually combining library files, resolving dependencies, maintaining the correct order, and stripping unused code is tedious and error‑prone—especially during a contest when minutes matter.
Beyond library management, competitive programmers face other repetitive tasks: creating a new file for each problem, copying sample test cases whenever the solution changes, hunting through a file picker to open the right source, and repeatedly compiling and testing by hand.
[Eitri](https://github.com/veryshyjelly/eitri) addresses these pain points by inte...
107.
Invitation to Alkhwarizm — 2019 by IIIT Allahabad 
[Aparoksha](https://aparoksha.org/) is back with the flagship coding event — **Alkhwarizm**
2 years back, we launched the first ever [External Rated Contest](https://blog.codechef.com/2017/03/09/a-star-studded-rating-system/) on **Codechef** — [Alkhwarizm 2017](https://www.codechef.com/ALKH2017).
Last year's [Alkhwarizm 2018](https://codeforces.me/blog/entry/58361) was a great success with over 1100 people participating in the contest.
If you have the appetite for algorithmic problem solving, then don't miss it out!
Contest link is here — [Alkhwarizm 2019](https://www.codechef.com/ALKH2019)
It will be a **5 hour individual contest** with algorithmic problem-set of diverse nature, and is **open for both students as well as professionals.**
The contest will comprise **10 problems**, and will be **rated for both divisions**.
The prizes include cash prizes...
108.
XTX Markets Global Forecasting Challenge Hello!
We are very pleased to cooperate with XTX Markets, thanks to whom we are able to hold the Global rounds. Four of the six of them are already passed and here are <a href="https://codeforces.me/blog/entry/68549">the current results</a>.
In short, XTX Markets is a leading quantitative-driven electronic market maker Launched in 2015, XTX Markets has rapidly become the number 1 FX spot liquidity provider by volumes globally, surging ahead of global banks.
<img src="/predownloaded/2e/e2/2ee2f0f95f05aae6ca6f47812dae2dc2aabf277b.png" style="width:200px; float:right; margin: 0 1em 1em 1em"/>
Thanks for supporting our community!
We are happy to announce that XTX recently launched the XTX Markets Global Forecasting Challenge, powered by Correlation One.
The XTX Markets Global Forecasting Challenge is an online competition for aspiring quantitative professionals, where contestants are tasked to develop a predictive model based on training data provided by XTX.
**Comp...
109.
Interview with TheOneYouWant, ask anything! Hello everyone,
Upd: Livestream has been scheduled. [Time in your timezone](https://www.timeanddate.com/worldclock/fixedtime.html?day=3&month=02&year=2024&hour=23&min=35&sec=0&p1=1799). You can tune in here.
Upd2: We recorded it with live audience today. Audio was lagging at some places. I will edit it by next week and upload it.
I wanted to share some exciting news with you. Recently, I launched my [YouTube channel](https://www.youtube.com/@aryanc403?sub_confirmation=1) and created a [community Discord server](https://discord.gg/gs5PSVuTfV). Up until now, I've mainly focused on hosting [post-contest](https://codeforces.me/streams/aryanc403) discussion streams on my channel. However, I have plans to diversify the content.
To kick things off, I'm thrilled to announce that I've invited my arch-rival, and my best friend, [user:TheOneYouWant,2024-01-17], to join me for an Ask Me Anything (AMA) session on my channel. We are planning to record this AMA sometime next month.
...
110.
I built a better CPH — and a better Codeforces while I was at it (FREE) **TL;DR -** CPH and Competitive Companion already parse samples and submit for you. CPOS does that too — but that's the boring part. The point is everything *around* it: a **browser companion** that turns the Codeforces page itself into an IDE (write and run your solution right there, plus rating-change predictions, deep profile analytics, head-to-head compare, a focus mode, and a cleaner UI), a **VS Code extension** that — unlike CPH — also renders the problem statement next to your code, and a **terminal app** that actually tells you what to solve next and how to reach your next rating. Free, open-source, MIT, and 100% local — no accounts, no servers, no tracking.
- **Source (MIT):** [github.com/Soham109/cpos](https://github.com/Soham109/cpos)
- **Browser companion (the good part):** [Chrome / Edge / Brave](https://chromewebstore.google.com/detail/gjnbapmjonegeeamdeahcoojgokeogmm) (Firefox source install in the repo)
- **VS Code extension:** [Marketplace]...
competitive programming. You launch `cpos` and it becomes your session: browse
problems, sync your rating, If you live in vim / neovim / helix, the terminal app steps out of the way to
launch your editor
111.
8VC Venture Cup 2017 Announcement <img src="http://assets.codeforces.com/images/8vc/8vc-venturecup-logo.png" style="float:right;margin:0 1em 1em 1em"/>
Hello Codeforces!
I'm pleased to announce the first championship hosted on the Codeforces platform. Welcome <b>8VC Venture Cup 2017</b>!
8VC will be hosting a coding championship on Codeforces. The championship will begin on January 15 and take place in 2 rounds.
The contest will occur in two rounds:
* The Elimination Round is online and takes place on <a href="https://www.timeanddate.com/worldclock/fixedtime.html?day=15&month=1&year=2017&hour=20&min=05&sec=0&p1=166">January 15, 17:05 (UTC)</a>.
Elimination Round follows regular Codeforces rules and consists of 7-8 problems. For this round, the complexity
of the problems will be comparable to a regular Codeforces round. There are no eligibility restrictions to participate in the round.
* The Final Round takes place on January 22, consists of 5-6 problems, and uses regular Codeforces rules. The...
furniture business. In just 12 months since launch, we've become the largest
custom furniture maker in
112.
ICPC/IOI Alumni Meetup in SF - Dec 4 Hello Codeforces!
To those who are in the SF Bay Area, let's gather for another meetup :)
On **Friday, December 4, 5–9 PM**, my friends at nFactorial Ventures are hosting their launch party at The House in San Francisco's Presidio. They invest in startups founded by former Olympiaders (ICPC/IOI/IMO/IPhO), and are bringing together **100+ Olympiad alumni, startup founders, AI researchers and investors**.
An interesting stat: Deedy Das from Menlo Ventures analyzed around 18,000 IMO/IOI/IPhO medalists over the last 25 years and estimated that they are **4000x more likely to become unicorn founders** than the average person.
**Speakers**:
- **Bill Poucher** — President of ICPC
- **Alex Mashrabov** — Founder & CEO of Higgsfield. 2x ACM ICPC World Finalist.
- **Nick Davidov** — DVC, seed investor in 7 unicorns
- **Nikunj Kothari** — Partner at FPV Ventures
- **Peter Zakin** — Partner at Upfront Ventures, Princeton ‘12, YC S10
Besides keyno...
**Friday, December 4, 5–9 PM**, my friends at nFactorial Ventures are hosting
theirlaunch party at, On **Friday, December 4, 5–9 PM**, my friends at nFactorial Ventures are
hosting theirlaunch party
113.
BFS, Multi-Source BFS, and Why the First Distance Is Already Optimal Hi everyone!
During the last three days I focused almost entirely on BFS on grids. Instead of solving many unrelated problems, I tried to understand why the algorithm works, where TLE comes from, and why some implementations are much faster despite using the same idea.
## multi-source BFS instead of many separate searches
The biggest takeaway was that if there are multiple sources, you should not run BFS from each of them independently.
My initial idea was to launch a separate BFS every time I found a new source. This may traverse the same cells many times.
If there are $k$ sources, the worst-case complexity becomes
$$
O(k \cdot n \cdot m).
$$
The correct approach is to put all sources into the queue at once, assign distance 0 to each of them, and run a single BFS.
```python
from collections import deque
q = deque()
for i in range(n):
for j in range(m):
if a[i][j] == 2:
dist[i][j] = 0
q.append((i, j))
```
Now ...
My initial idea was to launch a separate BFS every time I found a new source.
This may traverse the
114.
Guess the CF elo #1 _Note: This is the first part of 'Guess the CF Elo,' a series heavily inspired by the famous chess YouTuber GothamChess. [His youtube channel](https://www.youtube.com/@GothamChess)_
### **Quick Intro**
Most of you have probably heard of GothamChess and his famous "Guess the Elo" (GTE) series. Since the Codeforces and chess rating systems are quite similar, I decided to launch a similar series here. Idk how it will work out tho (it is my first blog after all), so feel free to leave your suggestions in the comments. Or just downvote (plis dont 😔)
### **Rules**
In this blog, I will analyze some real coders performance (chosen by me), covering a few of their latest contests. I will try to not make it too obvious or too hard. To participate, just write your guess in the comments. The only rule is — **it should be clear what exact number is your guess** (if you want your guess to be counted). For example "I think this guy is 1158" will be counted as a valid guess, while...
" (GTE) series. Since the Codeforces and chess rating systems are quite
similar, I decided tolaunch a, . Since the Codeforces and chess rating systems are quite similar, I decided to
launch a similar series
115.
1 on 1 Math Coaching (Free!) Hey! As Codeforces slowly turns into <strong>Mathforces</strong>, we know you're looking for ways to boost those math skills!
We at <u><a href="https://mathdash.com" style="color: #4500FF;"><strong>MathDash</strong></a></u> are excited to announce the launch of our new <strong>Ask for Help!</strong> feature!
<p>
Get <strong style="color:#1E90FF;">fast 1-on-1 help</strong> math tutoring at any time you want it! In order to get 1 on 1 help, we ask that you:
<ul>
<li>Choose a contest to participate in, and take the contest! You can choose <u><a href="https://mathdash.com/contests">any contest here</a></u> — if you are looking to train a specific topic, I'd recommend <u><a href="https://mathdash.com/contests?sortBy=1">looking here</a></u>. If you can't decide, message me and I can suggest one specifically for your level! </li>
<li>After completing a contest, simply hover over any problem you'd like assistance with, then click <strong style="color:#1E90FF;">Ask f...
;">MathDash are excited to announce the launch of our new Ask for Help, > are excited to announce the launch of our new Ask for Help! feature!
116.
From Tunisia to ICPC, Help Us Compete To Reach It! Hey Codeforces!
We’re a team of three Tunisian students [user:Moyogi,2025-11-12], [user:Iceberg,2025-11-12] and [user:GH1hatem,2025-11-12] who share one dream, to compete at the Arab and African Collegiate Programming Championship (ACPC 2025), one of the most prestigious contests in our region and qualify to the ICPC World Finals.
After months of intense training, sleepless nights, and thousands of practice problems, we qualified to represent Tunisia at ACPC!
Each of us has put years of effort into competitive programming. We all earned Gold Medals at the Tunisian Collegiate Programming Contest (TCPC), and one of us [user:Iceberg,2025-11-12] is already an ICPC World Finalist.
For us, this isn’t just a competition, it’s the result of countless hours of hard work, teamwork, and a deep love for problem-solving. It’s our chance to...
117.
First tour of Wide-Siberion Olympiad (2016) This year contestants implemented AI to manage robotic vacuum cleaners.
The game has massive-multiplayer style, which is strongly different from our previous games, which were usually either single-player (e.g. [in 2010](https://www.youtube.com/watch?v=GwdrpD7SRng)) or player-vs-player (e.g. [in 2013](https://www.youtube.com/watch?v=WbNQp144eEk)).
All 50 participating teams compete altogether in every game. Each player manages 10 robots, which drive on the round field. If a robot collides with another smaller robot (or with passive immobile "food"), then the former devours the latter, and its area is increased by the area of the devoured object. The player who devours everything wins (this surely happens since game field is gradually contracting). Game score of arbitrary player is defined as the overall area of all his robots at the best (for him) time moment. As size of robot increases, its speed decreases. That's why the game has turbo mode, which allows to double robot speed fro...
118.
a problem with topcoder contest applet HELLO EVERYBODY!
I have a problem with topcoder contest applet:
Application Error
Unable to launch the application.
Name" Competition Arena
Publishe : Topcoder , Inc.
Location : http://www.topcoder.com
detailes :
java.io.FileNotFoundException: http://www.topcoder.com/contest/classes/7.0/arena-client-7.0.6.jar
at sun.reflect.GeneratedConstructorAccessor2.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection$6.run(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection$6.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at sun.net.www.protocol.http.HttpURLConnection.getChainedException(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
at com.sun.deploy.net.BasicHttpRequest.doRequest(Unknown Source)
at com.s...
to launch the application. Name" Competition Arena Publishe : Topcoder , Inc.
Location, Unable to launch the application.
119.
Google Code Jam Statistics Hi!
As you probably know, there are some great websites for examining various statistics about past Google Code Jam rounds (e.g. https://a2oj.com/CodeJamTools/ or https://www.go-hero.net/jam). However, the last rounds these sites have are from the year 2017. I don't know for sure, but this might have something to do with the fact, that in 2018 Google launched their new Code Jam system and probably changed their APIs as well.
Long story short, I spent some time reverse-engineering the APIs and created a simple script to retrieve some data about various Google Code Jam rounds using the new API, as well as a simple website for viewing some statistics of round from 2018 and up. You can find the website here: https://vstrimaitis.github.io/google_codejam_stats/.
Here are some features which are currently supported:
- Some numerical stats (number of participants, number of perfect scores, etc.)
- Some charts (Top countries by number of participants / average score / most top-scor...
120.
How to expand the class of problems in CP without losing objectivity + simplifying organization **Who am I?** I took up ACM ICPC in 2006 as a student, went to the semi-finals 5 times, trained the teams of a provincial university, held several camps for schoolchildren from the zero level and above, and participated in the organization of regional competitions many times (ContestSfedu aka Championship of the South of the Russia aka GP of Azov Sea — Opencup). In recent years, I have been pursuing a career, so I do not actively participate in the sports program, but from time to time I continue to help in holding competitions in Taganrog.
**Why am I speaking out?** More and more often I find myself thinking that competition programming does not keep up with the rapidly changing world and it becomes more difficult to find arguments for students to do it. It's probably easier with schoolchildren, but it's only a matter of time. Do those who organize ICPC, school Olympiads, etc. understand this problem? — I don't know, because I'm not actively involved in the activities o...
black. Obviously, according to the results of the launch of each with each, a
completely objective
121.
Invitation to Hey Coach Coding Contest 2020. (Unrated) We [heycoach](https://heycoach.in/) Community invite you to take part in our coding contest which features 5 algorithmic + 1 hacking based coding problems.
The contest will start from :-- **22nd December 6pm and will last for 2 hours**.
Contest link:-[HCCC2020](https://www.codechef.com/HCCC2020)
**Separate registration for prizes is required see below for more details**
**ACM style ranking** and scoring that is binary format.
This contest is organized by Hey Coach A Tech interview and CP Coach website which focus on personalized guide for mastering technical concepts.
* Heycoach is a tech interview and competitive programming personalized coaching web based platform on which coach and students interact with each other to learn more. We offer courses on various Fields of computer science. We have launched our comprehensive guide to competitive programming on our website [Cp Coach](https...
122.
Launching a New Tool for Competitive Programmers: The First Code Compiler with
Hacking Capabilities!
Launching a New Tool for Competitive Programmers: The First Code Compiler with Hacking Capabilities! ###**Link To My Website**
[Try It Out!!](https://competitive-programming-compiler.tiiny.site/)
### **Features**
The website allows you to run code with [stdin](https://www.lenovo.com/in/en/glossary/stdin/?srsltid=AfmBOoo9WtF4PMa-UI2UUwqHa4e04Rc1LjtnBEkhQ0XFr9h5QUSSrikC) in [Python3](https://docs.python.org/3/tutorial/) or [C++17](https://en.cppreference.com/w/cpp/17) and it also allows you to smoothly try to hack someone else's solution smoothly via manually written test cases or generator (PS: It also tells if the code gives [TLE](https://www.reddit.com/r/leetcode/comments/ztca6u/sorry_im_new_to_leet_code_what_does_time_limit/) or [MLE](https://www.reddit.com/r/leetcode/comments/admwcg/what_does_memory_limit_exceeded_mean_when/)).
- Edit: As pointed out by [user:near_ai,2024-10-31], A new feature is added that doesn't let you run malicious code or the code which can potentially be harmful for the system.
- Edit: Added the feature that lets input allowed Time (in seconds) and ...
123.
Orz Chat CLI Is Here! (WOW) Orz Chat CLI Is Here!
==================
#### Hey everyone,
#### We are sure you haven’t forgotten about [Orz Chat](https://orzchat.com) — the browser version is still available.
#### But today we have something new: the **Orz Chat CLI**. Something that nobody asked for, yet here it is.
#### Now you can chat directly from your terminal without opening a browser.
---
<img src="https://i.ibb.co/SD6zb2Lp/image.png" alt="OrzChat CLI in action" style="display:block;margin:auto" />
---
## **Installing Orz Chat CLI**
#### <p>Install globally via npm:</p>
#### <pre><code><strong>npm install -g orzchat-cli</strong></code></pre>
#### <p>If you are seeing permission issues, you might need to use <code>sudo</code>:</p>
#### <pre><code><strong>sudo npm install -g orzchat-cli</strong></code></pre>
---
## **Usage**
#### <p>Run the following command to start chatting:</p>
#### <pre><code><strong>orzchat</strong></code></pre>
#### <p>This wi...
will launch the Orz Chat CLI application directly in your terminal.
#### [npmjs.com/package, ####
This will launch the Orz Chat CLI application directly in your terminal.
124.
IOI: database Last year I was deeply saddened by the fact that there isn't a unified place where one can view IOI results for all years. So I collected all the data I could find (and I found a lot) and put it in Excel. Then I edited the data so that the same person is written the same across all years. Afterwards I published it. There was hope that one day it could transform to [something IMO already has](http://imo-official.org/). But, time was passing by, the site wasn't magically appearing and this summer I decided to do it by myself. Currently the website has reached a state when it could be launched for a public use, so I'm happy to announce that today it was presented on the conference at IOI 2012 and is available at the following address:
[http://ioi.eduardische.com/](http://ioi.eduardische.com/)
==================
Despite the fact that the site is available for public use, it's still in development. Especially, it needs improvement in completing the database itself. Specifically, ther...
125.
Instant 1v1: CF-Blitz is Live ! Hi Folks!
<br><br>
The CF Blitz tournament on Codeforces is usually limited to top coders. I've always found that format insanely exciting — fast problems, pure pressure, and that race-to-AC feeling.
<br><br>
I really wanted to experience that kind of 1v1 intensity more often, not just once in a while. So I built <b>CF Blitz</b> — a simple place where anyone can jump in and feel that same blitz energy anytime.
<br><br>
<hr>
<div style="text-align: center;">
<a href="https://cf-blitz-production.up.railway.app/">
<img src="/predownloaded/cf/58/cf58e67e05157934ef981a53ec5df3042e3c21a0.jpg" style="width: 100px; border-radius: 5px;">
</a>
</div>
<br>
<b>What is CF Blitz?</b>
<br><br>
A minimalist platform for real-time 1v1 competitive programming using Codeforces problems.
<br><br>
No clutter. Just you, your opponent, and the clock.
<br>
<hr>
<b>Key Features</b>
<br><br>
<b>Seamless Login</b> — Sign in instantly with Google and link your Codeforces handle.
<br...
126.
CF College Standings — chrome extension ### Introducing CF College Standings: A Custom Standings Tab for Codeforces Contests
Hello Codeforces Community!
I'm excited to announce the launch of my new Chrome extension, **CF College Standings**, designed to enhance your contest experience on Codeforces. This extension aims to provide a more personalized view of contest standings by allowing users to filter the results based on their educational institution. Here's a detailed look at what this extension offers and how it can benefit you! If you're a student and just interested in seeing how your peers are performing, this extension offers a convenient way to track and compare standings within your community.
One of the standout features of this extension is that it not only works for ongoing contests but also allows you to view the standings of past contests. This means you can explore how your seniors performed in previous competitions and even review their submitted code. It's a fantastic way to learn from experienced ...
Codeforces Community! I'm excited to announce the launch of my new Chrome
extension, **CF College, I'm excited to announce the launch of my new Chrome extension, **CF College
Standings**, designed
127.
Codeforces Lite, An extension to enhance your Codeforces journey Hello competitive programmers!
On this auspicious occasion of Diwali, I’m thrilled to launch a game-changing extension:
Introducing Codeforces Lite!
This Chrome extension is all about making your experience on Codeforces smoother, more productive, and truly built for competitive programmers.
Download here: https://chromewebstore.google.com/detail/codeforces-lite/hgcgfmgjkfjmhoebifgmbfipinkkjgco
With Codeforces Lite, you’ll find:
-> Built-in Code Editor: Write, time, and submit code directly on the problem page—no more tab-switching or file uploads.
-> Code Saving: Efficiently saves up to 1000+ codes using a HashMap and Queue storage management.
-> Dark Theme: A carefully optimized dark theme, perfect for your late-night practice sessions.
-> Custom Templates: Start with a default template for contests and questions to speed up your workflow.
-> Enhanced UI: If CF's UI has felt overwhelming, this improved UI enhances navigation, structure, and makes CF easier to use.
...
Hello competitive programmers! On this auspicious occasion of Diwali, I’m
thrilled tolaunch a
128.
Yandex Cup 2025: ML-Track Hello CodeForces!
My name is Max ([user:msporyshev,2025-10-20]), I’m head of motion planning team at Yandex Autonomous Vehicles. We create neural networks that drive an autonomous car.
It happened that this year I lead Machine Learning track of Yandex Cup. And this year we have tried to significantly enhance this competition! The qualification started on October 15 and will last until November 5.
Problems
--------
For the qualification round, we have prepared three very challenging and interesting problems. They are all connected to our bleeding-edge AI technologies. To get ahead of other participants, it might be useful to read up-to-date research papers on the relevant topics, and maybe you'll even end up writing your own!
- Generating realistic images for self-driving car cameras based on a vector description of the scene. This is a small step towards world modelling, which is one of the most relevant research topics in robotics right now.
The only funtion it has right now is rating update notifications. And yes, it's ready to notify you about today's rating change.
Why am I writing this post now but not after the contest when everyone is nervously pressing F5 awaiting new digits in 'Rating' column? I want to test how it works. And the best way to test something is to invite testers. I hope that little VPS will survive Codeforces users' attack :)
If you want to help making it ready for today's contest, all you have ot do is head to http://cftoolkit.nic11.ru/rating_update_notifier , allow desktop notifications, wait a few hours and tell me if it worked correctly. In 2-3 hours after this post I will launch fake rating update no...
and tell me if it worked correctly. In 2-3 hours after this post I will launch
fake rating update, it worked correctly. In 2-3 hours after this post I will launch fake rating
update notification
130.
Wrong test cases of EDU pilot course segment tree part 2 step 4 "MOUNTAINS" ? I have submitted all [usaco guide solutions](https://usaco.guide/problems/ioi-05-mountain/user-solutions) and it gives "wrong answer on test case 2" for all of them
[Problem link](https://codeforces.me/edu/course/2/lesson/5/4/practice/contest/280801/problem/F)
In case that link doesn't open [Try this](https://www.iarcs.org.in/inoi/online-study-material/problems/mountain.php)
The Problem:
The Mountain Amusement Park has opened a brand-new simulated roller coaster. The simulated track consists of n
rails attached end-to-end with the beginning of the first rail fixed at elevation 0. Byteman, the operator, can reconfigure the track at will by adjusting the elevation change over a number of consecutive rails. The elevation change over other rails is not affected. Each time rails are adjusted, the following track is raised or lowered as necessary to connect the track while maintaining the start at elevation 0.
Each ride is initiated by launching the car with sufficient ener...
131.
Problem Writers: TCO19 Problem Writing Trip Opportunity Last year we had launched a problem writing Trip to 2019 TCO Finals. However, after feedback from the community and writers particularly, we have decided to increase the number of trips and also make it simple for you to earn a trip. We now have 5 trips to 2019 TCO Finals and 5 Trips to 2019 TCO Regional Events.
With 100 points, you can win a trip to the 2019 TCO Finals (location to be revealed later in the year)and with 65 points you can win a trip the nearest regional to your location.
You can submit your problems and earn points during any stage of TCO. All problems must be submitted correctly via the process explained here by midnight (12:00 am) Eastern time on the final day
*__Points__*
| Point Allocation | Easy | Medium | Hard |
| ---------- | ---------- | ---------- | ---------- |
| SRM Div 2 | 2 | 3 | 5 |
| SRM Div 1 | 5 | 10 | 20 |
*__Trips__*
| Trips* | Number of Trips | Points Requ...
132.
Single Command TopCoder Applet Installation for Arch Based Distros Greetings to the codeforces community,
I have added an Arch User Repository (AUR) package [topcoder-applet](https://aur.archlinux.org/packages/topcoder-applet) to make the installation of TopCoder applet on arch and arch derived Linux distributions easier using just a single command.
**The main advantages over following the steps provided by TopCoder officially at [INSTALLING TOPCODER'S VINTAGE ARENA](https://www.topcoder.com/thrive/articles/installing-topcoders-vintage-arena) are:**
- No need to find the right version of `javaws` to run the applet. The package installs the right java dependencies.
- Adds an icon to desktop and application launcher allowing users to run the applet with just one click. The package installs itself as any other GUI application.
Screenshot
------------------
Installation
------------------
**Installation with AUR package manager**
The package can be installed usi...
133.
Need an algorithm to solve the problem I am facing in my project One man launched a lottery game and wants to make money from it. Customers can buy lottery tickets online. Every ticket has a 12-digit number, each with a value from 0 to 9. Every night, there is a lucky draw. In the draw, the owner generates a lucky ticket number. According to the game rules, the winning customer will be given prize money.
The game rule:
There are 3 types of lottery tickets:
1. Straight
2. Ramble
3. Lucky
Rule for Straight: In order to get prize, the lottery tickets number should be exactly matched with the lucky ticket number.
The rule for Ramble: Both the lucky ticket number and the customer's lottery ticket numbers will be sorted in ascending order. After that, if the customer's ticket number exactly matches the lucky ticket number will get the prize.
Rule for Lucky: The number of matched digits with the lucky ticket number will be counted and will be prized accordingly. Example: Customer ticket number: 683819280374 and Lucky Ticket Number: 78...
134.
[Gym] The 2018 Arabella Collegiate Programming Contest Hello Codeforces,
I would like to invite you all to participate in the **2018 Arabella Collegiate Programming Contest**. The contest was originally held on $28^th$ of April, and it will launch in Codeforces Gym tomorrow [Saturday, 03 November 2018 10:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=The+2018+Arabella+Collegiate+Programming+Contest+-+Codeforces+Gym&iso=20181203T10&ah=5).
The problems were prepared by [user:justHusam,2018-11-02], [user:Lvitsa,2018-11-02], [user:Mohammad_kilani,2018-11-02], [user:Nada_Shamayleh,2018-11-02], [user:AbedAbuhijleh,2018-11-02], [user:H2A_TLE,2018-11-02], and [user:TheDealer,2018-11-02].
Thanks to [user:Hasan0540,2018-11-02], [user:Dehayat,2018-11-02], and [user:Zuhair,2018-11-02] for testing the problem set.
The duration of the contest is 5 hours, and the registration will be open 6 hours before the start of the contest.
Good luck to everyone, and I wish you all accepted solutions.
**UPD**: Registration is cur...
Collegiate Programming Contest**. The contest was originally held on $28^th$
of April, and it willlaunch in, **. The contest was originally held on $28^th$ of April, and it will launch in
Codeforces Gym
135.
[Gym] 2019 JUST Programming Contest Hello Codeforces,
I would like to invite you all to participate in the **2019 JUST Programming Contest** of Jordan University of Science and Technology. The contest was originally held on $23^{rd}$ of March, and it will launch in Codeforces Gym on [Friday, 29 March 2019, 13:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=%5BGym%5D+2019+JUST+Programming+Contest&iso=20190329T13&p1=%3A&ah=4).
The problems were prepared by [user:justHusam,2019-03-27], [user:Aristos,2019-03-27], [user:Lvitsa,2019-03-27], [user:H2A_TLE,2019-03-27], and [user:Thunder_r,2019-03-27].
Thanks to [user:Mockingjay,2019-03-27] for testing the problem set.
The duration of the contest is $4$ hours, and the registration will be open $6$ hours before the start of the contest.
Good luck to everyone, and I wish you all accepted solutions!
**Update: Registration is now open.**
**Update:** The contest has ended....
will launch in Codeforces Gym on [Friday, 29 March 2019, 13:00
UTC](https://www.timeanddate.com, }$ of March, and it will launch in Codeforces Gym on [Friday, 29 March 2019,
13:00 UTC](https
136.
Software vs. Hardware <div style="text-align: center;"><img src="http://truvoipbuzz.com/wp-content/images/WhyNokiasPeeinginthepantsanalogydoesnotm_731E/Hardware_vs_Software.png" /><br /></div><div style="text-align: justify;">There is a very interesting contradiction between productivity of modern hardware and speed of modern software. My first PC had 700 MHz CPU, 64 MB RAM and Windows 98. It took 2-3 minutes to start the operating system. The laptop I'm writing this post on has a dual-core 2 MHz CPU, 2 GB RAM and Windows 7. And it takes the same 2-3 minutes to start up.<br /></div><div style="text-align: justify;">The other exmaple. I use Opera. It fits me well except one thing - its launching time. I can't imagine what a browser should do to start in about 20 seconds. But it does. Chrome is supposed to be the fastest browser but it also doesn't show its window immediately after launching. Hey guys, it's just a browser! It must start as fast as Windows notepad does! It should just open its window which usu...
137.
Practice Kartik Arora Sheets on Codeblast! Hey all, thanks for the overwhelming response on our project: Codeblast. If you haven't seen yet, check it [here](codeblast.herokuapp.com).
[user:kartik8800,2021-08-31] has recently launched codeforces problemsets for us to practice and jump our codeforces rating to the moon.
Here is the [youtube link](https://www.youtube.com/watch?v=8gS50rVD1-E) for the same. He has awesome playlists on various topics ranging from CSES problemsets, to topic wise discussions.
As a less rated user of the almighty Codeforces, I really liked the idea of specific problems picked manually and with some backed up data.
But doing it with friends doubles the fun. So, I have included to practice from Kartik Arora's sheet as well in our project, [Codeblast](codeblast.herokuapp.com). You can also schedule contests now!
See [this](https://youtu.be/KyoIWANeOa8) for a quick 1 min tutorial on how to use the site(Well, actually you can skip it).
Thanks [user:Lord_Invincible,2021-08-31] as always...
138.
HORSE PROJECT: A Tokenized Intellectual Resource HORSE PROJECT: A Tokenized Intellectual Resource
-------------------------------------------------------
Ukrainian version is available here: https://telegra.ph/HORSE-PROJECT-Token%D1%96zovanij-%D1%96ntelektualnij-resurs-04-12
Greetings from the **“unlimited_excellence”** team, which includes:
- Andrii Mykhalko ([user:likespro,2025-04-12])
- Denys Oryshych ([user:oryshych.d,2025-04-12])
- Nazar Rak ([user:nazik_rachok,2025-04-12])
- Alex Bondarenko ([user:AlexJenious,2025-04-12])
- Viktor Dobosh ([user:mr.grory,2025-04-12])
- Kostya Chuiev ([user:LaGipeR,2025-04-12])
- Ivan Shneider ([user:kx04,2025-04-12])
- Heorhii Mykhalko ([user:shad0w_,2025-04-12])
- Serhii Oryshych ([user:Oryshych,2025-04-12])
We believe that intellectual work has value. That is precisely why we created **HORSE Token** — a tool to tokenize efforts in the worlds of competitive programming, mathematics, and education.
The Idea Behind the Project and the First Version
---------------------------...
------------------------------------------------------ To celebrate the launch
of **HORSE Token**, we are organizing the **Horse.Run, launch of **HORSE Token**, we are organizing the **Horse.Run() Contest**,
featuring **10 randomly
139.
VIM for competitive programming _Hello, Codeforces!!_
Many people ask for the best text editor for the programming contest. So, according to me vim is a great tool for competitive programming. It is not very comfortable to use it at first but after some time you will feel it is the best text editor ever made. So,
I am going to help setup VIM(for windows) and make is ready to use for competitive programming.
WHY VIM??
==================
I suggest, just try vim and you will get to know.
But, if you are curious you can refer: https://medium.com/@fay_jai/what-is-vim-and-why-use-vim-54c67ce3c18e
You can download vim from https://www.vim.org/download.php, just download the Self-installing executable file, install it by keeping all the settings default.
Now, just launch Gvim from the start menu and you will enter a page where you would not be able to understand much but don't worry I am here to help you.
At the start, you will be in normal mode, just type `:e ~\desktop\main.cpp`, this will create a new fi...
Now, just launch Gvim from the start menu and you will enter a page where you
would not be able to
140.
[Gym] 2017 JUST Programming Contest 4.0 Hello Codeforces,
I would like to invite you all to participate in the **2017 JUST Programming Contest 4.0** of Jordan University of Science and Technology. The contest was originally held on $16^th$ of September , and it will launch in Codeforces Gym tomorrow [Saturday 23 September 2017 14:30 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=%5BGym%5D+2017+JUST+Programming+Contest+4.0&iso=20170923T1430&p1=1440&ah=4).
The problems were prepared by [user:justHusam,2017-09-22] and [user:Vendetta.,2017-09-22].
Thanks to [user:I-Love-Islam,2017-09-22] and [user:The-Legend,2017-09-22] for sharing the ideas of two problems.
The duration of the contest is 4 hours, and the registration will be open 6 hours before the start of the contest.
Good luck for everyone, and I wish you all Accepted solutions.
**Note: Don't forget to use fast I/O methods.**
**UPD**: Registration is currently open.
...
, and it will launch in Codeforces Gym tomorrow [Saturday 23 September 2017
14:30 UTC](https, ^th$ of September , and it will launch in Codeforces Gym tomorrow [Saturday 23
September 2017 14:30
141.
A2SV G5 — Round #46 Editorial [Here](https://codeforces.me/contestInvitation/255862732d6b680f4d8bba55cf0c744a1b4226f1) is the link to the contest. All problems are from Codeforces' problemset.
#### [A. Chocolate Bar](https://codeforces.me/gym/557458/problem/A)
<spoiler summary="Solution">
<p>
To solve this problem, let's use the following greedy algorithm.
</p>
<p>
Let's sort the prices of chocolate bars in increasing order, after which we will go from left to right and take chocolates that have a price not less than $l$, but not more than $r$ until we run out of money.
</p>
<p>
The number of chocolate bars that we took will be the answer to the problem.
</p>
<p>
Time complexity: $O(nlogn)$.
</p>
</spoiler>
<spoiler summary="Code">
```python
import sys
from collections import Counter
input = lambda: sys.stdin.readline().rstrip()
t = int(input())
for _ in range(t):
n, l, r, k = map(int, input().split())
a = list(map(int, input().split()))
a.sort()
ans = 0
...
142.
[Gym] 2018 JUST Programming Contest 1.0 Hello Codeforces,
I would like to invite you all to participate in the **2018 JUST Programming Contest 1.0** of Jordan University of Science and Technology. The contest was originally held on $17^th$ of March, and it will launch in Codeforces Gym tomorrow [Friday 13 April 2018 13:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=%5BGym%5D+2018+JUST+Programming+Contest+1.0&iso=20180413T13&p1=%3A&ah=4).
The problems were prepared by [user:justHusam,2018-04-12] and [user:Lvitsa,2018-04-12].
Thanks to [user:MahmoudHamdyY,2018-04-12] for sharing the idea of one problem.
The duration of the contest is 4 hours, and the registration will be open 6 hours before the start of the contest.
Good luck for everyone, and I wish you all Accepted solutions.
**UPD**: Registration is currently open.
**UPD**:
During the contest today, and after 2 hours and 51 minutes, we received a notification f...
will launch in Codeforces Gym tomorrow [Friday 13 April 2018 13:00
UTC](https://www.timeanddate.com, ^th$ of March, and it will launch in Codeforces Gym tomorrow [Friday 13 April
2018 13:00 UTC](https
143.
Breaking Limits at 14: Harvard CS50, My Book, and a New Learning Platform Hello Codeforces!
At 14, I’ve reached three milestones that prove age is no barrier to ambitious goals:
Conquered Harvard’s legendary CS50 course — the one many adults drop halfway through
Written and published my first book on decision-making
Built and launched my own learning & project platform from scratch
No formal CS background — just persistence, curiosity, and a lot of debugging (in code and in life).
This is the full story — the challenges, the strategies, and why I believe mindset matters far more than age in tech.
(You can see the full post here: https://www.facebook.com/share/p/1DKy9HBr39/)
[cut]
Hello everyone!
I have three incredible milestones to share — and I’m both excited and humbled to reveal them. At just 14 years old, these achievements show that age is no barrier to serious learning, creativity, and impact.
I COMPLETED Harvard’s most demanding computer science course: CS50 — and I didn’t just pass, I thrived.
Harvard’s CS50 is globally known for ...
144.
CP POTD Exciting Announcement!
Introducing [**CP POTD**](https://asksenior.in/problemoftheday) by Ask Senior!
[Ashish Kumar](https://www.linkedin.com/in/ashish-kumar-a225a3a2/) and [I](https://www.linkedin.com/in/jaskaran-singh-8b8450200/) are thrilled to announce the launch of **CP POTD**(Competitive Programming Problem of the Day) by [Ask Senior](https://www.linkedin.com/company/asksenior/)!
What's in store for you?
**Daily Challenges:** We bring you a new and challenging problem every day to sharpen your competitive programming skills.
**Video Solutions:** Tune in at 11 PM every day for video solutions to the POTD, guiding you through the thought process and techniques.
**Concept Refresher:** Facing challenges with the concepts? No worries! Our CP sheet includes topic videos and a plethora of problems to help you brush up on your skills.
**Interactive Learning:** Have questions or doubts? We've got you covered! I'll be sharing insights and answering your queries on the ...
/in/jaskaran-singh-8b8450200/) are thrilled to announce the launch of **CP
POTD**(Competitive, ://www.linkedin.com/in/jaskaran-singh-8b8450200/) are thrilled to announce the
launch of **CP POTD
145.
NUST MISIS is better then HSE??? Hello teem and whatever dont worry teem xDD !!! Now i m just studiing in MISIS UNIVERSE right now about 1 years (LOL)
And by this topic i must say that this nice (not call (bad)) Universd in Moscow city from Russia. From the now moment i say more details about this issuae:
1) In the first i could say about foodplace in MISIS education: IT IS A VERY AMAZING FOOD WHICH EXPLORING MY BRAIN AND EVERY TIME I GET RUN TO MY LESSONS BECOSE WAITING TO EATING THIS GODLESS LAUNCH. (By the way in conclusion with HSE UNIVERSE it has cost 100 rubles (about 2$ dollars in america) as a nice deal to eating and i am dont be hungry alll day becose it is a very amazing food which exoliring me. This is ours tipical breakfast for student (free): 
2) In the second i need to mark my phisical teacher which is a Americon Films Actor he is name Yurii Borisov and he was oscar nominator in americon films...
EXPLORING MY BRAIN AND EVERY TIME I GET RUN TO MY LESSONS BECOSE WAITING TO
EATING THIS GODLESSLAUNCH
146.
Thoughts on DeepSeek R1?? So DeepSeek launched their R1 model which they claim is on par with OpenAI-O1.
More details here: [Link to X post](https://x.com/deepseek_ai/status/1881318130334814301)
This is a big update for CP as the model is open sourced and the chat can be accessed for free. As for the R1 model itself, I think its great particularly the chain of thought feels like that of a human.
I tested it out on 6 different problems in total, 3 problems of 1700 rating, 1 problem of 1800, 1 of 1900 and one unrated problem from recent contest (Div. 2 — 996).
This is what happened:
- [Problem 1](https://codeforces.me/problemset/problem/1550/C) — It managed to solve this in the first attempt.
- [Problem 2](https://codeforces.me/problemset/problem/1478/C) — Again managed to solve in the first attempt.
- [Problem 3](https://codeforces.me/problemset/problem/1625/C) — For this problem, it took an extra prompt.
- [Problem 4](https://codeforces.me/contest/2055/problem...
147.
2023 Recap Happy New Year to everyone who's already stepped into 2024, and to those of us still hanging out in 2023! I usually like to spend a bit of time looking back at the year that's been. So, let's dive into this little trip down memory lane together and see what 2023 had in store for us!
- On January 19th, the [Universal Cup](https://ucup.ac/) was launched as an alternative to the OpenCup, primarily to facilitate systematic training for teams with a focus on preparing for the International Collegiate Programming Contest (ICPC). In its inaugural season, the Universal Cup attracted participation from 750 teams, representing over 300 organizations worldwide, which participated in 22 stages.
- From February 18th to 26th, the first edition of the [Osijek Competitive Programming Camp](https://ocpc.mathos.unios.hr/) took place. A total of 74 teams participated, with 13 teams attending the event in person in Osijek, Croatia. The second edition of the camp occurred in September.
- Also in Febr...
148.
Users With Inspirational Progress Charts I often enjoy looking through the top rated users here on CF and seeing the progress chart on their profile, it is really motivating to see where the current grandmasters where say 2,3,4+ years ago.
For example there are users I've found such as [user:RAVEman,2015-05-23] who just launched out of the starting line with force as shown:
There are also users who started off with a consistent pace, and then hit a peak somewhere midway (I always wonder what caused this). For example [user:ACRush,2015-05-23]
Lastly my personal favorite profile to look at for inspiration is [user:matrix,2015-05-23]. This user started just a bit higher than I have, with early days greatly resembling my own progress chart. I especially like how much it bounces around, purple/green/back to purple. Shows the determination of the user!
I know that there is a lot more than just a pictur...
149.
masterpiece.txt Bee Movie Script
According to all known laws
of aviation,
there is no way a bee
should be able to fly.
Its wings are too small to get
its fat little body off the ground.
The bee, of course, flies anyway
because bees don't care
what humans think is impossible.
Yellow, black. Yellow, black.
Yellow, black. Yellow, black.
Ooh, black and yellow!
Let's shake it up a little.
Barry! Breakfast is ready!
Ooming!
Hang on a second.
Hello?
- Barry?
- Adam?
- Oan you believe this is happening?
- I can't. I'll pick you up.
Looking sharp.
Use the stairs. Your father
paid good money for those.
Sorry. I'm excited.
Here's the graduate.
We're very proud of you, son.
A perfect report card, all B's.
Very proud.
Ma! I got a thing going here.
- You got lint on your fuzz.
- Ow! That's me!
- Wave to us! We'll be in row 118,000.
- Bye!
Ba...
All right, launch positions!
150.
Error while trying to launch topcoder arena Please help me. I want to be able to participate in SRM 724.
I got this error when trying to launch topcoder arena.
~~~~~
Exception in thread "main" java.lang.UnsupportedClassVersionError: net/sourceforge/jnlp/runtime/Boot : Unsupported major.minor version 52.0
at java.lang.ClassLoader.findBootstrapClass(Native Method)
at java.lang.ClassLoader.findBootstrapClassOrNull(ClassLoader.java:1073)
at java.lang.ClassLoader.loadClass(ClassLoader.java:414)
at java.lang.ClassLoader.loadClass(ClassLoader.java:412)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:312)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)
~~~~~
I'm running it on Achlinux using icedtea-web
Error while trying to launch topcoder arena, I got this error when trying to launch topcoder arena., launch topcoder arena. ~~~~~ Exception in thread "main"
java.lang.UnsupportedClassVersionError: net
151.
International Data Analysis Olympiad (IDAO 2020) 
Hello, Codeforces!
[HSE Faculty of Computer Science](https://cs.hse.ru/en/) and [Yandex](https://yandex.com/company/) launch registration for the 3rd International Data Analysis Olympiad ([IDAO 2020](https://idao.world/)). The platinum partner of IDAO 2020 is Qiwi.The Olympiad includes two stages:
**Online Stage (Jan 15 – Feb 11, 2020):**
- Track 1: Traditional machine learning competition on Yandex.Contest platform. You will need to make new predictions and upload them to the automatic verification system.
- Track 2: Come up with a solution for the same problem, keeping within a rigid framework of time and memory used.
**Final (April 2-5, 2020):**
- top 30 teams according to the Online Stage results will be invited to the on-site final, which will be held on April 2-5 in Yandex office, Moscow.
- In the final 36 hours of the competition, participants will try not just to train the model, but...
/) launch registration for the 3rd International Data Analysis Olympiad ([IDAO
2020](https://idao.world
152.
NUST MISIS is better then HSE??? Hello teem and whatever dont worry teem xDD !!! Now i m just studiing in MISIS UNIVERSE right now about 1 years (LOL)
And by this topic i must say that this nice (not call (bad)) Universd in Moscow city from Russia. From the now moment i say more details about this issuae:
1) In the first i could say about foodplace in MISIS education: IT IS A VERY AMAZING FOOD WHICH EXPLORING MY BRAIN AND EVERY TIME I GET RUN TO MY LESSONS BECOSE WAITING TO EATING THIS GODLESS LAUNCH. (By the way in conclusion with HSE UNIVERSE it has cost 100 rubles (about 2$ dollars in america) as a nice deal to eating and i am dont be hungry alll day becose it is a very amazing food which exoliring me. This is ours tipical breakfast for student (free): 
2) In the second i need to mark my phisical teacher which is a Americon Films Actor he is name Yurii Borisov and he was oscar nominator in americon films...
EXPLORING MY BRAIN AND EVERY TIME I GET RUN TO MY LESSONS BECOSE WAITING TO
EATING THIS GODLESSLAUNCH
153.
Practice Like It's a Real Contest — CF Battleground (v1.1.0) is Live!!! ### Hey CF Community!!
First of all, a big **THANK YOU** to everyone who used the platform, gave feedback, and helped it grow. The overwhelming response from the community inspired me to build a better, more **feature-rich experience**.
After many trials, fixes, and feature requests — I’m excited to launch **v1.1.0** of the platform today!
#### Improvements from the v1.0.0:
- Score calculation issue resolved when creating a room — **no more inconsistencies!** (Credits: [user:thevyomanaut,2025-07-07])
- Dynamic questions every time a new contest is created — **no repeats!** (Credits: [user:uwu12,2025-07-07])
- Improved question selection logic — now fetched using problem names, which fixes the **Div1/Div2 mismatch** issue. (Credits: [user:Eyes_on_me,2025-07-07], [user:apollo07,2025-07-07])
#### What’s New in v1.1.0?
- **Real-time Chat** added inside rooms to collaborate and discuss. (Credits: [user:1ota,2025-07-07])
- **Admin controls**: Room creator can now remove ...
excited to launch **v1.1.0** of the platform today! #### Improvements from the
v1.0.0: - Score, experience**. After many trials, fixes, and feature requests — I’m excited to
launch **v1.1.0** of
154.
Sans Assistant v2.0: Destroying Newbie Excuses Since Today Hi Codeforces!
As many of you from my country know, 11th grade has officially come to an end, and we just had our Last Bell ceremony. For me, this means it's time to say goodbye to the Republic National Olympiad (RFO/RIO) ecosystem and shift my sights entirely to higher-level grinds like EJOI and beyond. (Assuming I can actually handle that much pressure without my brain frying, haha ;_:)
I know that while I am writing this, some absolute legends from the 11th-grade community are out there securing their shiny gold medals that will be given by there school. Huge congrats to them!
However... my own Last Bell ceremony didn't go down anywhere near as well as I thought it would. To be honest, I'm pretty tilted. The organizers completely glanced over my track record--they didn't even mention that I made it to the Finals 3 times and won a medal! To make it worse, I didn't even get a basic certificate, while some people who didn't even place walk away with one?
Worst of all, they ...
155.
Just curious about different perspectives to approach this problem ### Problem Statement
You are given two lists of integers, `T` and `A`, where:
1. `t[i]` represents the launch time of the i-th missile.
2. `a[i]` represents the position where you need to be to watch the i-th missile launch.
Starting at position `0`, you can move up to `X` units per second. Your objective is to maximize the number of launches you can watch. You can watch a launch if you are at the required position `a[i]` exactly at the time `t[i]`.
---
### Input Format
The first line contains two integers `N` and `X`—the number of missile launches and your maximum speed.
The second line contains `N` integers `t1, t2, ..., tn` — the times of the launches in the mission in increasing order.
The third line contains `N` integers `a1, a2, ..., an` — the positions along the boundary where you need to be to watch each launch closely.
---
### Output Format
Print the maximum number of launches that you can watch closely.
---
### Constraints
1<=N<=2*1...
need to be to watch each launch closely., speed `2` for `3.5` seconds to reach there just in time to watch the missile
launch. - **At time 10, the number of launches you can watch. You can watch a launch if you are at the
required position `a[i, #### Explanation He cannot reach any missile launch positions on time, so he
can't watch any, 1. `t[i]` represents the launch time of the i-th missile. 2. `a[i]` represents
the position where, ]` represents the launch time of the i-th missile. 2. `a[i]` represents the
position where you need to be
156.
Translating emaxx Dear All,<br>
Like any other contestant in ACM-ICPC or online competitions, you probably passed by e-maxx.ru/algo. The website is a very valuable algorithm bank along with explanation and sample codes. The only problem is that it's all in Russian. I am sure Google translate can do a proper job in the easier algorithms but in the harder ones every word counts and it's usually not very sufficient.<br>
We have been thinking how valuable it would be if we have such a bank translated into English. To do that we basically need a Russian coder that knows English well and willing to do it. Translating all the algorithms will probably take some time and possibly nobody will be willing to give that much time with no return.<br>
The plan we have in mind is the following:<br>
- We find a good Russian coder with good knowledge of English willing to do the translation and ask him how much money he can do that for.<br>
- We launch a kickstarter campaign targeting anybody who will benefit f...
money he can do that for.
- We launch a kickstarter campaign targeting anybody who will benefit, launch a kickstarter campaign targeting anybody who will benefit from the
translation (which is
157.
Invitation to Club of Programmers IIT (BHU) YouTube Channel Hello, Codeforces community
The Club of Programmers, IIT BHU is excited to announce the launch of COPS YouTube channel.
This channel will largely focus on being a helping hand to all our fellow mates who are eagerly working in the field of Competitive Programming, Machine Learning, and Development.
The highlight of the channel will be meticulously crafted editorials and tutorials for some must-know Competitive Programming, Machine learning, and Web Development topics. Additionally, we will also pour out content for beginners to enable them to kickstart their journey in the CS fields above.
So, for everyone looking for a place to get their share of fun while coding, check out our YouTube channel for more! It will contain all resources needed for our community with lots of learning waiting for you!
YouTube Channel link: https://www.youtube.com/channel/UC01TZlNfu29QgG4FmUqVsdg?view_as=subscriber
Hello, Codeforces community The Club of Programmers, IIT BHU is excited to
announce thelaunch, The Club of Programmers, IIT BHU is excited to announce the launch of COPS
YouTube channel.
158.
General Release of Fast Olympic Coding Hello everyone, I am finally satisfied with my extension to openly announce Fast Olympic Coding for VSCode and its derivatives!
Fast Olympic Coding went through 2 major releases since [the last time I announced it](https://codeforces.me/blog/entry/131003). I have kept the design principle of optimal screen utilization while being jam packed with functionality. The design has been re-imagined to match the experience of Visual Studio Code. And, here are some of the new major tools added:
- **Debugging testcases directly in real-time!** You do not have to launch the debugger and send inputs manually anymore
- Interactive testcase support for both judging and stress testing
- Time and memory limit
There are too many hidden changes for me to write here, but the end goal has always been to **provide a native VSCode experience for competitive programming.**
**The extension is available for download at [Visual Studio Marketplace](https://marketplace.visualstudio.com/items?itemNa...
- **Debugging testcases directly in real-time!** You do not have to launch the
debugger and send, : - **Debugging testcases directly in real-time!** You do not have to launch
the debugger and send
159.
September Mega Cook-Off 2015 on CodeChef Hi everybody!
I invite you to participate in the CodeChef September Mega Cook-Off at [https://www.codechef.com/COOK62](https://www.codechef.com/COOK62). The problemset of the contest is prepared by me.
I hope you will like the problems: some of them require outstanding algorithmic thinking, some of them require brilliant coding skills — anyway, I'm pretty sure, that no one will get bored during the contest. ;)
**Time:** 20th September 2015 (21:30 hrs) to 21st September 2015 (00:00 hrs). (Indian Standard Time — +5:30 GMT) — Check your [timezone](http://www.timeanddate.com/worldclock/fixedtime.html?msg=CodeChef%3A+September+Cook-Off+2015&iso=20150920T2130&p1=44&ah=2&am=30).
**Details**: [https://www.codechef.com/COOK62](https://www.codechef.com/COOK62)
**Registration**: You just need to have a CodeChef handle to participate. For all those, who are interested and do not have a CodeChef handle, are requested to [register](https://www.codechef.com/signup) in order to ...
160.
KYCS — (Know Your CodeForces Submission) I have created certain CodeForces submission visualization some days back (can be found in my previous blog entries). And getting a really positive response, I thought of combining all of them at one place and make them easy to use which obviously needs deploying to web and needs nothing more than a good internet. So, I have come up with this small Dash python app which allows us to create really nice data analytics app and the main thing is its OpenSource.
Just follow the instructions written in the top left corner of the [page](https://kycs.herokuapp.com/) when it's launched from the web.
They will look something like this:
It's as easy to follow as it sounds. (Link to the [app](https://kycs.herokuapp.com/))
<br>
Also if someone would like to contribute, then source code is [here](https://github.com/JeetKaria06/KYCS).
![Output2](/predownloaded/1a/0c/1a0c481d01e6149295618160670720825c4c7b81....
161.
Exposing FAANG Youtubers and their LOOTS in term of REVOLUTION!!! We will be talking about one of the famous ex-FAANG You-tubers today, who is exploiting today's youth to fill their pockets. This post is necessary so that they stop the exploitation in the name of revolution. From glorifying resignations to dropping out from college, these shameless creatures, don't miss a chance to use these things for content.
After being fired from Amazon because of excessive use of logo's and showing on-call details over a vlog[he says he resigned since he was asked to choose between yt and amazon, apparently none of the other amazon you-tubers were asked to]. He decided to glorify by creating a Linkedin post where he states "am taking a stand for 3.5L students" and then comes up with a Netflix production level movie on why he resigned. Holy SHITTTTT!!
Gets all the hype, grows in numbers, now thinks of using these numbers efficiently. He plans to start paid courses, and goes across to meet the worst of company which is Unacademy's founder in November [proo...
courses would have backfired, since all he provided was roadmaps till now.
Decides tolaunch his, . - Runaway after that, and give them lame excuses for being busy. - Launch a
cohort with minimal, Decides to launch his free DSA course and promises to bring revolution by
completing the course in
162.
Button "hide problem tags" Hi everyone!
I know of two problem solving modes on *Codeforces*
1. Write a contest online or in a virtual competition mode. Then you can't open the solutions of other participants, look through the tests, watch the problem tags and all sorts of information that can help you figure out the task.
2. Solve problems from the archive, in free manner. This can be used for training, it is convenient to sort tasks by specific topics or rating.
So, when solving the problem in the second way, I ran into the problem that I see its tags. It gives me an advantage that I don't want to have. A kind of hint. To solve this problem, I can launch a virtual participation in the contest where the task was. However, then I will not be able to get additional information about the task before the end of the virtual. What if I want to think for an hour and then look at the tags, for example.
The "hide tags" button, which I did not find (maybe it already exists), would help me here. I think it wou...
gives me an advantage that I don't want to have. A kind of hint. To solve this
problem, I canlaunch a, kind of hint. To solve this problem, I can launch a virtual participation in
the contest where the
163.
C++ runtime problem in windows Hi everyone,
I write this blog because I encountered a rather weird issue, maybe anyone here has the same issue or even has solved this?
I was participating in a contest earlier when I tried to compile & run for problem B and my code doesn't run ＞︿＜
### My case:
This code below compiles and run, I can see `Hello` printed in my terminal
~~~~~
#include <bits/stdc++.h>
using namespace std;
int main() {
vector<int> v;
cout << "Hello";
// v.push_back(2);
return 0;
}
~~~~~
However when I uncomment `v.push_back(2)` it compiles but doesn't run! (I don't see `Hello` in terminal)
Commands I used:
`g++ main.cpp -Wall -o main`
`.\main.exe`
There's no warning or error message.
I have tried compiling with MSYS64 (my main) and MSVC x64, same results.
Yesterday it was working fine, so maybe something broke my c++ runtime today.
Here's a list of what I did today before running to this problem:
- installed Anaconda,
- installed git,
- insta...
grabbing Ubuntu. C++ works as expected now, just launch VS Code through the
bash terminal you'll get
164.
[Gym] 2018 ACM Amman Collegiate Programming Contest Hello Codeforces,
I would like to invite you all to participate in the **2018 ACM Amman Collegiate Programming Contest (AmmanCPC 2018)**. The contest was originally held on the 5th of May, and it will launch in Codeforces Gym on [Saturday, 2 June 2018 10:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=2018+ACM+Amman+Collegiate+Programming+Contest&iso=20180602T10&p1=1440).
The problems were prepared by [user:Kudo.,2018-05-30] (Ali Fadel), [user:Vendetta.,2018-05-30] (Ibraheem Tuffaha) and [user:The-Legend,2018-05-30] (Abdulmajeed Alzoubi).
Thanks to [user:Flerynn,2018-05-30] (Yosef Darwish), [user:M.Dawwas,2018-05-30] (Mohammad Abu Dawwas), [user:abo_od303,2018-05-30] (Abdalrhman Ali) and [user:Qumair,2018-05-30] (Fares Obaid) for sharing the ideas of four problems, to [user:Motarack,2018-05-30] (Motasem AL-Kayed), [user:abo_od303,2018-05-30] (Abdalrhman Ali) and [user:SAFWAN.K,2018-05-30] (Safwan Olaimat) for testing some of the problems and to [user:Ownograp...
Contest (AmmanCPC 2018)**. The contest was originally held on the 5th of May,
and it willlaunch in, will launch in Codeforces Gym on [Saturday, 2 June 2018 10:00
UTC](https://www.timeanddate.com
165.
Graph Algorithms for Competitive Programming: A New YouTube Playlist Playlist link: https://www.youtube.com/playlist?list=PLUpzFxGnjRcvRupvAGyUC1DUhVGM_C-fa
Hey Codeforces community!
I'm thrilled to announce the launch of my new YouTube playlist dedicated to graph algorithms for competitive programming. As a passionate competitive programmer myself, I understand the importance of mastering graph algorithms, and I'm excited to share my knowledge with all of you.
For each topic, I've curated a set of problems from the awesome CSES Problem Set, which I believe will help solidify your understanding.
I'm committed to making this playlist as helpful and informative as possible, and I value your feedback. If you have any suggestions for topics you'd like to see covered or specific problems you'd like me to include, please let me know in the comments below (or on the youtube channel videos). Your input will help shape the direction of the playlist and ensure that it meets the needs of the community.
Thank you for taking the time to read about my ...
Codeforces community! I'm thrilled to announce the launch of my new YouTube
playlist dedicated to, I'm thrilled to announce the launch of my new YouTube playlist dedicated to
graph algorithms for
166.
Codeforces Notes — A Useful Chrome Extension Hi everyone!
We have recently built a **Chrome Extension** (screenshots below) that allows you to **take notes on problem page.**
[Link to the extension](https://chromewebstore.google.com/detail/codeforces-notes/opblhodpkchjjlphbdkkcklioeekpmjc)
Some people maintain a CSV for this, but no need anymore.
Developers:
[Shubham Goel](https://codeforces.me/profile/shubhamgoel0711) & Me
**Some use-cases of the extension:**
<spoiler summary="Click me">
- You can take notes while solving the problem, or after you've solved it.
- Once you solve a problem, noting down the key idea helps you retain it for a long time.
- You can revisit / revise later.
- Soon, we will launch an export to CSV feature — imagine having everything that you've learnt on one page!
</spoiler>
**Features to be added:**
- Export question name, link, rating, and note to CSV.
- View all notes on the profile page.
**Screenshots:**
Once you login to the extension, this will appear...
idea helps you retain it for a long time. - You can revisit / revise later. -
Soon, we willlaunch an, . - Soon, we will launch an export to CSV feature — imagine having everything
that you've
167.
Algorithms and Data Structures in JavaScript Hello Readers!
I've recently launched [JavaScript Algorithms and Data Structures](https://github.com/trekhleb/javascript-algorithms) repository on GitHub with collection of classic algorithms and data-structures implemented in ES6 JavaScript with explanations and links to further readings and YouTube videos. There is also [Algorithms and Data Structures YouTube playlist](https://www.youtube.com/playlist?list=PLLXdhg_r2hKA7DPDsunoDZ-Z769jWn4R8) that contains all the videos mentioned in that repository so you may just go and take this hand-made online learning course :)
So I guess you've already grasp main idea of the project - ** helping developers to learn and practice algorithms and do it in JavaScript** .
[cut]
To make this process even smoother I've tried to put some **graphical illustrations** for each algorithm and data structure where it was possible just to make the idea behind those algorithms to be easily grasped and memorized.
You also may find some practical i...
168.
The Daily Coding Question blog! Tips for competitive programming Hello Codeforces!
As some of you may remember, I posted here about [The DCQ](https://thedcq.com), a free email service which sends you a problem every day of the week and also it's explanation and sourcecode.
We have 270 users at the moment, and want to know your feedback, so we can tailor the problems to your needs.
Also, we have launched our [blog](https://thedcq.com/blog)! We will post weekly articles regarding different topics.If you want to see a specific article, drop a comment! The first article is about improoving at competitive programming!
For the ones that haven't signed up yet, please do so and tell us what you think! Remember, we will reach full capacity at 350 users( after 350 users, we won't be able to afford the email service).
Update: We have reached 350 users, and from now on, we will have to introduce paid subscriptions. You will have to option to invite 3 friends for a free month with most of the benefits, or pay $3.49 if you don't wish to do so.
...
169.
CodeForces Helper : Drop your valuable suggestions First of all, if you still haven't tried the app then visit [Link to play store](https://play.google.com/store/apps/details?id=com.codeForces.Helper)
-----------------------------------------------------------------------------------
Hey guys, we launched the **CodeForces Helper app** on play store around one month back and it feels very nice to see great response.
As of now it has **500+ installs** and **4.9 rating ( total 39 )** on play store.
It really motivate us seeing such responses, so We are going to work on the app and will add some amazing features as well as we are planning to update some existing things for your best user experience.
If you have any suggestion for new features then drop your valuable suggestion in comments :)
Even if you want to suggest some changes in existing features then let us know :)
**Another developer** : [user:vraj1408,2020-12-24]
KEEP CODING !
<a href="https://ibb.co/VvRMxpK"><img src="https://i.ibb.co/9q6yh3M/cf1.j...
170.
Discover the World Programming Workshop 2020 We’re happy to announce we’ve just launched **Discover the World Programming Workshop**. The registration is now open!
The workshop will be held **online** from the 6th till the 11th of September 2020. You will have five contests, lectures and problems analyses during these days. Time zone will suit the majority of the registered participants. **Participation is paid.**
Suppose you don’t have time to participate online simultaneously with everyone. In that case, you’ll be able to reach the contests anytime you like during a month after the start and and watch recorded lectures and problem analyses.
Participants are welcome to register in the following divisions:
**div A/B** — high difficulty, suitable for the current ICPC finalists and regional ICPC TOP-100 teams. This division will work well for those whose Codeforces rating is between 1900 and 2400
**div C** — middle difficulty, suitable for the participants of regional ICPC contests with Codeforces rating betwe...
171.
Exciting Job Opportunity: Problem Curator and Doubt Solver Hello Codeforces Community
==========================
Are you passionate about problem-solving, algorithmic challenges, and helping others navigate through coding hurdles? If so, we have an exciting job opportunity for you!
#### Position: Problem Curator and Doubt Solver
#### Compensation: $300-$500
#### Working Hours: 3-4 hours per day (flexible, based on requirements)
#### Location: Remote
### _Eligibility : Only people having rating above 1600 can apply_
### About Us:
We are a dynamic team of enthusiasts who are on road to launching a startup dedicated to promoting and enhancing young enthusiasts. To further enrich the user experience, we are expanding our team and looking for talented Problem Curators and Doubt Solvers to join us.
### Job Description:
As a Problem Curator and Doubt Solver, you will play a crucial role in shaping the coding challenges and providing assistance to community members facing coding-related doubts. Your responsibilities will...
172.
java.dfs inquisition I'd like to know, how to launch dfs on java, to make it work pretty fast. $n = 2\,300\,000$.
Submit [submission:54911336], says that on codeforces (windows, java32 1.8.0_162) `time in dfs = 126ms`.
Locally (windows, java64 11.0.1) i have `time in dfs = 13913ms`. The difference is 100 times!
[user:Petr,2019-06-01] (windows, java 1.8.0_181) gets 15 seconds.
Command line options are `java -XX:NewRatio=5 -Xms8M -Xmx512M -Xss64M`. Taken from [here](https://codeforces.me/blog/entry/43696).
How long it works for whom? (i'm interested in time, os/processor, java version, command line options)
How to reach 126ms locally?
**UPD:** <br>
Locally if i add `-XX:TieredStopAtLevel=1` [(help)](http://qaru.site/questions/240705/what-exactly-does-xx-tieredcompilation-do) i get `387ms`. <br>
Command line options "exactly as on codeforces" locally on java64 give me the same time `13913ms` $\pm\varepsilon$. So it's important to use java32.
I'd like to know, how to launch dfs on java, to make it work pretty fast. $n =
2\,300\,000$.
173.
[Update] CF Custom Contests: Level Up with New Analytics & Firefox Support! Hey everyone! Last week, I launched **Codeforces Custom Contests**, a [Chrome extension](https://chromewebstore.google.com/detail/iafalaippdkpmfpicnhoccfbbkgnelpg?utm_source=cf-blog) (now on [Firefox](https://addons.mozilla.org/en-US/firefox/addon/codeforces-custom-contests/) too) to instantly create personalized contests. I just wanted to thank you all for your support as there are over 300 new users in just one week!
**Summary for New Users:** Create custom contests instantly and analyze your results to efficiently train and improve your rating! See more info in the [previous post](https://codeforces.me/blog/entry/142733)
I’ve incorporated feedback and suggestions on the previous post and shipped a major update. Here’s the details!
What's New
------------------
- **Advanced Post-Contest Analytics:** Track your progress and find your weaknesses with detailed performance metrics. See accuracy by tag/rating, a contest history, an upsolve list, and more!
- **Problem Tags Fil...
174.
Announcing turboCP, a tool to help upskill faster in competitive programming Hi, I'm officially announcing **turboCP** — my personal effort to help competitive problem solvers practice and upskill with greater clarity and consistency.
turboCP is a platform which provides you, as a problem solver, everything you need to up your game, all at one place.
1. **Daily Challenges**: You will get a daily problem from codeforces which is uniquely selected for your skill level. The problems level up as you do.
2. **Streaks**: We all know how addictive streaks are. Solve the daily problem to maintain streaks and stay consistent.
3. **Detailed Analytics**: See which topics you haven't practiced or struggle with, average time you take to solve questions of different difficulties, accuracy, detailed roadmaps and much more.
4. **Custom Contests**: Create and practice with your own timed custom contests, with detailed contest analysis.
**Join the waitlist here** — [https://turbocp.vercel.app/](https://turbocp.vercel.app/)
(check Promotions label ...
I’d love for you to join the waitlist and get priority access at launch!
175.
CF community & CF API I'd like to start a discussion on how CF community is involved or at least notified about the changes happening in CF and in CF API in particular.
It seems that there are people more or less constantly working on implementing some new features on CF. And sometimes we can see blog posts from [user:MikeMirzayanov,2015-05-28] or somebody from CF team highlighting a list of changes which happened during some period, but these posts are very rare, they are published like once or twice per year, while it seems that we have something changed almost every month. CF has very strong community, some people from the community do something on their own built on top of CF web site or CF API ([submit solution from command line](http://codeforces.me/blog/entry/14786), [VIM plugin](http://codeforces.me/blog/entry/16635), my CF achievements project). For all of us it is critical to be aware of changes happening on CF. For example this submission script stopped working after CSRF security fix. Ano...
script stopped working after CSRF security fix. Another example I found today:
since it'slaunch CF
176.
Alexander the Great Alexander III of Macedon (Ancient Greek: Ἀλέξανδρος, romanized: Aléxandros; 20/21 July 356 BC – 10/11 June 323 BC), most commonly known as Alexander the Great,[c] was king of the ancient Greek kingdom of Macedon from 336 BC until his death.[d] He was the son of Philip II, born to him by his fourth wife, Olympias, and ascended to the throne at the age of 20 after Philip was assassinated. Alexander spent most of his reign conducting a lengthy military campaign throughout Asia and Egypt, and by the age of 30, he had created one of the largest empires in history, stretching from Greece to northwestern India.[2] He was undefeated in battle[e] and is widely considered to be one of history's greatest and most successful military commanders.[3][4][5]
Born in Pella, Macedon, Alexander was tutored by the philosopher and polymath Aristotle until the age of 16. In 335 BC, shortly after assuming the throne of Macedon, he launched a campaign in the Balkans and reasserted control over Thrace and p...
177.
AlgoAtlas Update: We're Back & Stronger After Epic Community Response! **Hello again, Codeforces community!**
First off, WOW! The response to [AlgoAtlas](http://algoatlas.tech) has been absolutely overwhelming—in the best and most challenging ways possible. Our compiler servers practically melted from all your test submissions!
**What Happened?**
Our initial launch post generated far more interest than we anticipated (thank you!), and our compiler infrastructure couldn't handle the sudden traffic surge. Many of you experienced timeouts or slow performance—I sincerely apologize for that frustration.
**Good News: We've Fixed It!**
I'm excited to announce that AlgoAtlas is back online with:
- Completely rebuilt compiler infrastructure capable of handling 10x more concurrent users
- Optimized execution pipeline with significantly faster response times
- Enhanced reliability with auto-scaling capabilities to handle traffic spikes
New Features Just Added:
**AI Code Analyzer**
1. Deep analysis of your algorithmic approach (not just syntax...
**What Happened?** Our initial launch post generated far more interest than we
anticipated (thank, , or if you encountered issues during our initial launch, I encourage you to
visit us again at https, launch post generated far more interest than we anticipated (thank you!), and
our compiler
178.
[Gym] 2017 ACM Amman Collegiate Programming Contest Hello Codeforces,
I would like to invite you all to participate in the **2017 ACM Amman Collegiate Programming Contest (AmmanCPC 2017)**. The contest was originally held on $19^th$ of August, and it will launch in Codeforces Gym on [Friday 25 August 2017 14:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=2017+ACM+Amman+Collegiate+Programming+Contest+&iso=20170825T14&p1=1440&ah=4).
The problems were prepared by [user:Hasan0540,2017-08-23], [user:justHusam,2017-08-23], [user:AliOsm,2017-08-23], [user:Alaa_AbuHantash,2017-08-23], and [user:yosef_darwish,2017-08-23].
The duration of the contest is 4 hours, and the registration will be open 6 hours before the start of the contest.
Good luck for everyone, and I wish you all Accepted solutions.
**UPD:** Registration is currently open.
**UPD: The contest will start in 30 minutes.**
Contest (AmmanCPC 2017)**. The contest was originally held on $19^th$ of
August, and it willlaunch in, it will launch in Codeforces Gym on [Friday 25 August 2017 14:00
UTC](https://www.timeanddate.com
179.
[!] besterds wanna see your place without cheaters?
==================
To solve this problem, i created besterds — extension that shows your pure rank.
How2Install?
------------------
1. Open the GitHub repo: https://github.com/nileqq/besterds
2. Drop a star if you like the idea, then download the project: Code => Download ZIP
3. Unpack ZIP
4. Launch server: python -m src.app.backend.server
5. enter Google/Firefox:
- For Google: chrome://extensions => Load unpacked => choose folder ..\besterds\src\app\dist\chrome
- For Firefox: about:debugging#/runtime/this-firefox => Load Temporary Add-on => ..\besterds\src\app\dist\firefox\manifest.json
----
❗ Besterds uses an ML model — a binary classifier — so it can make mistakes.
Please don’t blindly trust the extension or accuse someone of cheating just because Besterds marked them as suspicious.
Use it as a fun and helpful tool, not as a final verdict.
Its v1. I'll update it soon.
4. Launch server: python -m src.app.backend.server
180.
Launching My CSES Dynamic Programming Video Series! Hi everyone!
I’ve recently started a YouTube channel where I am uploading detailed solutions to the Dynamic Programming section of the CSES Problem Set. If you’re someone who wants to master DP from the ground up with clean explanations, multiple approaches, and real coding walkthroughs, this might be useful for you.
I have already uploaded solutions to 5 questions(RECURSION+TABULATION)
CSES DP Playlist Launch Video:
https://www.youtube.com/watch?v=gElByOcqJRQ
YouTube Channel:
https://www.youtube.com/@NikhilDixit-k1e
Also share, subscribe and like my channel !!
CSES DP Playlist Launch Video: https://www.youtube.com/watch?v=gElByOcqJRQ
181.
[Gym] ACM Arabella 2019 Hello Everyone.
I would like to invite you to participate in ACM Arabella 2019 which will be launched in GYM [contest_time:102263]
You will be given 13 problems to solve in 5 hours, The contest difficulty is similar to Div2 Contests.
The problem-set were prepared by [user:Hiasat,2019-06-28] , [user:Motarack,2019-06-28] , [user:Roze,2019-06-28] , [user:Ayoub.Aref,2019-06-28] , [user:Dehayat,2019-06-28] , [user:Obada-AlAbbadi,2019-06-28] , [user:Kilani,2019-06-28] , [user:AbedAbuhijleh,2019-06-28]
Good luck to everyone.
182.
I broke Codeforces, what should I do? [submission:92716508]
They say no access, here's the code: https://ideone.com/0CWKP6
Here are the task: https://codeforces.me/gym/102386/problem/K
I do not know how to add a photo of the problem, but here is the link to it: https://yadi.sk/i/NUYcr1IVfeN_gA
The package received a "Test Refusal". As I understand it, the problem in generating randomness in the checking system
And even when we started to write virtual participation (from the one who launched the virtual participation), we only had a countdown for one of the participants, and the rest could view the tasks. Everything worked before.
Upd: Participants could enter the competition in coach mode, as far as I understand, it was impossible to do this before
There is 1.5 hours until the next round, can the problem I found spoil it?
183.
Team Battle Mode is Live on Codeforces Duel! Team Battle Mode is Live on Codeforces Duel!
I’ve just launched a brand new **Team Battle Mode** on **[Codeforces Duel](https://cf-1v1.vercel.app/)** — where coding meets gaming!
Now you can team up with your friends and compete against other teams in a **PUBG Mobile–style match lobby**, making problem-solving more exciting than ever.
There are two fun ways to play:
**First Solve Mode:** Be the fastest — whoever solves first gets the points!
**Total Solves Mode:** Codeforces-style — solve as many as you can, and the team with the most points wins.
We’ve already hit **650+ users** and seen **300+ duels** take place — and it’s just getting started!
Watch the demo video here: [**watch here**](https://youtu.be/sLlFd_Ud7KQ)
Try it out: **[https://cf-1v1.vercel.app/](https://cf-1v1.vercel.app/)**
184.
Unable to start TopCoder Arena on Ubuntu 18.04 Currently I am unable to open TopCoder Arena on Ubuntu 18.04. It gives an error message
~~~~~
net.sourceforge.jnlp.LaunchException: Fatal: Launch Error: Could not launch JNLP file. The application has not been initialized, for more information execute javaws/browser from the command line and send a bug report.
at net.sourceforge.jnlp.Launcher.launchApplication(Launcher.java:582)
at net.sourceforge.jnlp.Launcher$TgThread.run(Launcher.java:945)
~~~~~
Earlier it was working fine. But I guess, the recent updates are the issue for the problem. I have tried the solutions from this two sources [https://forums.linuxmint.com/viewtopic.php?t=294555](https://forums.linuxmint.com/viewtopic.php?t=294555) and [AskUbuntu](https://askubuntu.com/questions/1134881/icedtea-8-cannot-run-any-jnlp-application-maybe-due-to-openjdk-11) .
Till now I am unable to find a way to start the Arena.
I have also tried solutions from this blog [https://codeforces.me/blog/entry/13613?](https://codeforces.co...
~~~~~ net.sourceforge.jnlp.LaunchException: Fatal: Launch Error: Could not
launch JNLP file. The
185.
Accurate memory accounting for programming contests (part 1) <span class="Apple-style-span" style="font-family: arial , sans-serif;font-size: small;">
<p>The memory accounting is the part of programming contest
environment which is almost never done right. And even if it's done
right, it doesn't seems so to the extent that people will complain
about it. A lot.</p>
<p>So let's start with choosing our platform first (Windows), and
briefly describe the most common mistakes people do (aside from
saying "contest platform is simple, I'll write one in no time").</p>
<h2>Chapter 1, in which we learn how to do <a style="font-family: arial , sans-serif;color: rgb(0,62,168);">GetProcessMemoryInfo</a></h2>
<p>
<a style="font-family: arial , sans-serif;color: rgb(0,62,168);">CreateProcess</a> (and
similar functions) give us this handle, which we can later use
in <a style="font-family: arial , sans-serif;color: rgb(0,62,168);">GetProcessMemoryInfo</a> call,
which will in turn give ...
, will launch everything as an admin user, won't do process time accounting, ...
186.
BABBAR HYPOCRITE - Destroyed my LIFE I am sure you would have read the previous post about Babbar where he was exposed very badly.
If you have not, please read [this](https://codeforces.me/blog/entry/95372).
Today I will share what happened with me and I will expose this hypocrite again. Babbar was caught because of violation of Amazon rules. This guy was about to be kicked out, but he resigned before that, as he had an offer of Microsoft.
He is such a manipulater, that he decided to latch on it and create a video with cinematic shots, as high as Netflix quality production. Have you ever seen someone glorifying resignation with a "cinematic shot video"?
In this video he mentions how he was wrongly attacked, and he has used the term "middle class" to gain sympathy. So I am keeping some points which will prove that he is actually a hypocrite.
1. He mentions in his video, that he has just created 12 videos on roadmaps. Bruhhhh, you don't need to add a title "roadmap" to make a roadmap video. Stop foo...
doings which shows you do it only for money. You made a discord launch video,
which was of 5 minutes
187.
[Gym] 2017 JUST Programming Contest 3.0 Hello Codeforces,
I would like to invite you all to participate in the **2017 JUST Programming Contest 3.0** of Jordan University of Science and Technology. The contest was originally held on $26^th$ of August , and it will launch in Codeforces Gym on [Wednesday 30 August 2017 15:00 UTC.](https://www.timeanddate.com/worldclock/fixedtime.html?msg=%5BGym%5D+2017+JUST+Programming+Contest+3.0&iso=20170830T15&ah=4)
The problems were prepared by [user:Vendetta.,2017-08-28], [user:justHusam,2017-08-28], [user:Alaa_AbuHantash,2017-08-28], and [user:0xAC,2017-08-28].
The duration of the contest is 4.5 hours, and the registration will be open 6 hours before the start of the contest.
Good luck for everyone, and I wish you all Accepted solutions.
**UPD:** Registration is currently open.
**UPD: The contest will start in 30 minutes.**
it will launch in Codeforces Gym on [Wednesday 30 August 2017 15:00
UTC.](https://www.timeanddate.com, ^th$ of August , and it will launch in Codeforces Gym on [Wednesday 30 August
2017 15:00 UTC.](https
Announcement of 2017 JUST Programming Contest 3.0
188.
Reply Code Challenge — Teen Edition On the **15th of March 2019**, the Italian company Reply will hold the second edition of the Reply Code Challenge, a team-based coding competition open to students and professional coders. In its first edition, this competition involved more than 7,700 contestants from 67 countries.
This year, a new contest will also be launched: the Reply Code Challenge Teen Edition, open to and designed for teenagers from the ages of 14 to 19. This contest, created in collaboration with the Italian Olympiads in Informatics staff, will challenge teams of up to four young students to solve algorithmic problems. **The winning team will receive €5,000 to be divided among the members, the second ranked team will receive €2,000 and the third ranked team will receive €1,000.**
To take part, sign up at https://challenges.reply.com/ before March 14th, create a team, and participate on March 15th: both the Standard Challenge and the Teen Edition will be held online from 4.30pm CET to 8.30pm CET. Partici...
189.
[Gym] The 2018 JUST Collegiate Programming Contest Hello Codeforces,
I would like to invite you all to participate in the **2018 JUST Collegiate Programming Contest**. The contest was originally held on $31^st$ of March, and it will launch in Codeforces Gym on [Saturday 28 July 2018 10:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=The+2018+JUST+Collegiate+Programming+Contest+-+Codeforces+Gym&iso=20180728T10&p1=1440&ah=4).
The problems were prepared by [user:justHusam,2018-07-25], [user:Lvitsa,2018-07-25], and [user:Nada_Shamayleh,2018-07-25].
Thanks to [user:Light,2018-07-25], [user:Dehayat,2018-07-25], and [user:AbedAbuhijleh,2018-07-25] for testing the problem set.
The duration of the contest is 4 hours, and the registration will be open 6 hours before the start of the contest.
Good luck to everyone, and I wish you all accepted solutions.
**UPD**: Registration is currently open.
Programming Contest**. The contest was originally held on $31^st$ of March,
and it willlaunch in, **. The contest was originally held on $31^st$ of March, and it will launch in
Codeforces Gym on
190.
Metaverse- Take a leap into the Future Facebook’s decision to rename itself with the new corporate name Meta Platforms Inc. -marked an appropriate endpoint for a year in which the relatively murky concept of the Metaverse became one of the most hyped buzzwords in technology. Many people laughed when Facebook renamed itself, but do you actually know the reason behind it??
Metaverse has set the trend for all internet things so much that it now has its own Wiki definition. Metaverse has already become a part of our lives without us knowing about it. People who play Roblox, Fortnite, Minecraft, etc., are already living in metaverses and won’t likely hesitate to join another where their friends and the things they enjoy all exist.
-History:
Before understanding metaverse, let us go back to when the internet was invented. British computer scientist Tim Berners-Lee published the first website on August 6, 1991. He dreamt of linking together information with hypertext that could be viewed via a web browser. Years later, he c...
191.
[Gym] 2017 JUST Programming Contest 2.0 Hello Codeforces,
I would like to invite you all to participate in the **2017 JUST Programming Contest 2.0** of Jordan University of Science and Technology. The contest was originally held on $1^st$ of April, and it will launch in Codeforces Gym tomorrow; [Friday 7 April 2017 13:00 UTC.](https://www.timeanddate.com/worldclock/fixedtime.html?msg=2017+JUST+Programming+Contest+2.0&iso=20170407T13&p1=%3A&ah=4)
The problems were prepared by [user:justHusam,2017-04-06] and [user:Alaa_AbuHantash,2017-04-06].
Thanks to [user:Vendetta.,2017-04-06] for testing the problem set.
The duration of the contest is 4 hours, and the registration will be open 6 hours before the start of the contest.
Good luck for everyone, and I wish you all Accepted solutions.
**UPD:** Registration is currently open.
**UPD: The contest will start in 30 minutes.**
will launch in Codeforces Gym tomorrow; [Friday 7 April 2017 13:00
UTC.](https://www.timeanddate.com, ^st$ of April, and it will launch in Codeforces Gym tomorrow; [Friday 7 April
2017 13:00 UTC.](https
Announcement of 2017 JUST Programming Contest 2.0
192.
Looking for volunteers to open source and maintain CodeDrills recommender We launched the CodeDrills [recommender](https://recommender.codedrills.io/) 6 years ago and since then it has been used to recommend problems for practice more than **10 million** times! Unfortunately, over time, I got busy with other stuff and could not maintain it. Now I plan to open source the recommender so that it can be maintained by the community. For that I am looking for some volunteers from the competitive programming community.
CodeDrills has kindly agreed to continue to bear the hosting and other charges for the recommender.
More details [here](https://discuss.codedrills.io/t/looking-for-volunteers-to-open-source-and-maintain-codedrills-recommender/1810)
Let me know if you are interested in the same.
Cheers
193.
Online graph editor tool — csacademy.com Hello, Codeforces!
We have recently launched a [graph editor](https://csacademy.com/app/graph_editor/) tool. Feel free to use it whenever you want to visualise or create a medium size graph. It currently supports up to 30 nodes.
For any feedback, leave your comments here :).
194.
TCO Announcement Fun Marathon On Friday Topcoder announcement date and location for TCO17 finals — **October 20-24, Buffalo, NY**.
And today we launched a themed Marathon match [WaterfallFishing](https://community.topcoder.com/longcontest/?module=ViewProblemStatement&rd=16930&pm=14615) — rated but without any TCO points. It will run for one week (till May 29), and will have this week's Data Science Weekly Challenge associated with it.
195.
[Gym] The 2018 JU Collegiate Programming Contest Hello Codeforces,
I would like to invite you all to participate in the **2018 JU Collegiate Programming Contest (JUCPC2018)** of the University of Jordan. The contest was originally held on the $6^{th}$ of April, and it will launch in Codeforces Gym tomorrow [Friday, 20 April 2018 13:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=%5BGym%5D+The+2018+JU+Collegiate+Programming+Contest&iso=20180420T13&ah=4).
The problems were prepared by [user:justHusam,2018-04-19] and [user:Lvitsa,2018-04-19].
Thanks to [user:Hiasat,2018-04-19], [user:Light,2018-04-19], and [user:TheRoot,2018-04-19] for testing the problem set.
The duration of the contest is 4 hours, and the registration will be open 6 hours before the start of the contest.
Good luck to everyone, and I wish you all accepted solutions.
it will launch in Codeforces Gym tomorrow [Friday, 20 April 2018 13:00
UTC](https
196.
Online graph editor tool — Edgitor Hello, Codeforcers!
I have recently launched a [graph editor tool](https://edgitor.chunlaw.io/) to illustration on vertex-edge graph editing. You may create and visualise your graph by simply stating the list of edges.
Highlight Features:
- Arranging graph as a tree/grid/circle
- Flipping, rotating or transpose the graph
- Zooming in/out
- Panning the view port
- Supporting both undirected and directed graph
- Importing/exporting as JSON
- Saving as SVG
- No limitation on the number of nodes
For any feedback, you may leave your comments here or leave comments in [Github issues](https://github.com/chunlaw/edgitor/issues).
197.
ICPC/IOI Event in San Francisco on Dec 4 Hello Codeforces!
It’s been a while.
On Friday, December 4, 5–9 PM, [nFactorial Ventures](https://nfactorial.ventures), the fund I started, is hosting its launch party at The House in San Francisco's Presidio. We invest in startups founded by former Olympiaders (ICPC/IOI/IMO/IPhO), and are bringing together 100+ Olympiad alumni, startup founders, AI researchers and investors.
An interesting stat: Deedy Das from Menlo Ventures analyzed around 18,000 IMO/IOI/IPhO medalists over the last 25 years and estimated that they are 4000x more likely to become unicorn founders than the average person.
Speakers:
- Bill Poucher – President of ICPC
- Alex Mashrabov – Founder & CEO of Higgsfield. 2x ACM ICPC World Finalist.
- Nick Davidov – DVC, seed investor in 7 unicorns
- Nikunj Kothari – Partner at FPV Ventures
- Peter Zakin – Partner at Upfront Ventures, Princeton ’12, YC S10
Besides keynotes, there will be "What? Where? When?" (intellectual team game aka ЧГК), a poker tou...
started, is hosting its launch party at The House in San Francisco's Presidio.
We invest in startups
198.
База известных олимпиадников **Hi there! I got a brilliant idea. How about creating a website that has the names of various well-known personalities in the field of programming?**
Ukraine already has such a website — https://data.oi.in.ua/people. But I would like to make it more interesting and so that it is not limited to Ukraine alone. We must do everyone from the CIS countries, to begin with. It would also be nice to add not only the winners of the 4th stage (at the country level) or the winners of the IOI (or ICPC final), but also the winners of regional or city olympiads. Well, in general, it is necessary to follow not only among schoolers, but also among students.
The Codeforces platform is very popular among programmers, but by launching this database built into Codeforces, the site will become a little more interesting for people who are already elderly programmers and now, for example, are looking for employees.
For example, a person comes to get a job. He is asked to tell about himself. But...
199.
New Orz Puzzle I’ve just launched a brand new tile puzzle where an image is split into a grid, and you solve it by sliding entire rows and columns. Shifting a row or column simply wraps the tiles around to the other side. I’d love to hear how you approach it in the comments.
[Orz Tiles Puzzle (0, 0)](https://orztiles.shop/puzzle/0/0)
<div style="font-family: sans-serif; line-height: 1.5; color: #000; padding: 16px; border-radius: 8px; display: inline-block; text-align: center;">
<a href="https://orztiles.shop/puzzle/0/0">
<img
src="https://i.ibb.co/XfWZ2sCZ/image.png"
alt="Orz Tiles Puzzle"
style="width: 450px; display: block; margin: 0 auto 16px;"
/>
</a>
</div>
The puzzle is gonna be different for each tile, so browse the gallery for more.
Do you think the current grid is too easy? Should we upgrade it to a 4x4 or even larger? Let me know your thoughts.
Don’t forget to leave an **orz** in the comments if you liked the idea.
200.
2016 PSUT Coding Marathon Hello Competitors,
I would like to invite you all to participate in the follow up of Third Coding Marathon of Princess Sumaya University for Technology. The contest was originally held on April 30, and it will launch in Codeforces Gym tomorrow; [May/07/2016 10:00](http://www.timeanddate.com/worldclock/fixedtime.html?day=7&month=5&year=2016&hour=10&min=0&sec=0&p1=166).
The problems were prepared by [user:2Nodes,2016-05-06], [user:SaMer,2016-05-06], and Dr. Ibrahim ([user:earlgray,2016-05-06]).
The contest will be held with extended ACM ICPC rules. You'll be given **14** problems to solve within **270** minutes. Some of the problems have two parts (A and B), where A is easier than B, and the statement of B depends on the statement of A. The difficulty of the contest is similar to Codeforces Div. 2 contests.
Good luck to you, and I hope you can enjoy the problemset.
Note: Don't forget to use fast I/O methods.
Sumaya University for Technology. The contest was originally held on April 30,
and it willlaunch
Announcement of 2016 PSUT Coding Marathon
201.
Feedbacks regarding CPDojo Recommendation system Hi CF community,
Recently I launched CPDojo problem recommendation system which recommends problems for a user so that they can reach their desired rating-group (next rating-group).
I just wanted to ask... did someone face issues where you clicked on 'Generate' button and you didn't get recommendations ?
Or any other issues / defects you found ? or want to give some different feedback regarding the recommended problems ?
Pls do let me know. Thank you !
Note: I'll use this blog to look into defects related to recommendation system.
Recommender can be found here : [here](https://www.cpdojo.com/recommender)
202.
[Gym] ACM Arabella 2017 Hello Everyone.
I would like to invite you to participate in ACM Arabella 2017 which will be launched in GYM [Friday 14/04/2017 14:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?day=14&month=4&year=2017&hour=17&min=0&sec=0&p1=166)
You will be given 13 problem to solve in 5 hours, The contest difficulty is similar to Div2 Contests.
The problem-set were prepared by [user:Hasan0540,2017-04-13] , [user:Hiasat,2017-04-13] , [user:Motarack,2017-04-13] [user:1am,2017-04-13] , [user:Mohammad_kilani,2017-04-13] [user:abed.jaradat,2017-04-13] , [user:Alaa_AbuHantash,2017-04-13] and Ahmad Alkhaldi.
Good luck for everyone.
203.
Inputting a symbol in an integer variable Hey codeforces! One day I launched MinGW Studio and checked this simple code:
~~~~~
#include <iostream>
using namespace std;
int main() {
int n = 50;
cin >> n;
cout << n;
return 0;
}
~~~~~
I wrote 'z' on the console and saw '50'. Nothing strange. But when I did the same on the last version of CodeBlocks, I saw '0'. Can someone explain me what exactly happens in there and why it happens in CodeBlocks and doesn't happen in MinGW Studio?
204.
Update: SMS AI Launching Pro Mode with Dual-Engine Multimodal Image Logic Hey everyone,
Following up on my previous build log, I have just pushed a major architectural update to SMS AI by Deltacoders to separate free computational tiers from premium processing workflows:
[SMS AI](https://sms-ai-delta.lovable.app/)
Thanks to the feedback from the community, the platform now handles multimodal text-to-image prompts using a dynamic tiered structure to keep performance ultra-fast for everyone.
What's new in this system update:Free Tier Inline Generation: Free users can now generate images directly inside the standard conversational chat history panel. This operates on a highly optimized, lighter execution model labeled as GPT-2 Access Mode.Pro Mode Premium Suite: Subscribed users ($20/mo) now get access to a dedicated, separate Advanced HD Image Pop-up Window. This panel routes requests directly to a hyper-realistic GPT-5 Pro / Advanced Engine for blazing-fast, uncompressed visual generations.Optimized Code Engine: General syntax highlighting parameters, mul...
205.
Initial heap size set to a larger value than the maximum heap size in Round 137 G Round 137 problem G (https://codeforces.me/contest/1743/problem/G) Java submission always fails with following error:
Error occurred during initialization of VM
Initial heap size set to a larger value than the maximum heap size
The problem has an usual memory limit per test of 4 megabytes. The error is likely due to value of -Xmx is smaller than -Xms in the test launch.
-Xms: This specifies initial heap size for JVM
-Xmx: This specifies maximum heap memory size for JVM
-Xmx is smaller than -Xms in the test launch. -Xms: This specifies initial
heap size for JVM
206.
CodeFights is officially launched, already out of beta [CodeFights](https://codefights.com) just went out of beta and the biggest change is that there are 3 new languages supported — C++, Python and Java (previously tasks were only in JS). My favorite feature is solving challenges where most people seem to compete for getting shortest source code to given task (tasks are mostly easy so main challenge is usually solving it with a shortest code among all solvers). One issue I see is that Python solutions have big advantage since they are very short, also it is pretty annoying to see people copy-pasting solutions from each other, hopefully it will be given some solution soon.
By the way, users who perform good enough can post challenges themselves, would love to see new ones!
207.
Topcoder's New Arena — Inviting Proposals **An all-new Arena**
Hi All,
We are planning a new arena and it is coming but with a twist! Instead of Topcoder working on the arena we are going to fund the community to manage and build out the new version of the arena.
We are going to be launching a CRFP ([first draft](https://docs.google.com/document/d/e/2PACX-1vTCHL95n_eXUaebYq_llxsoaT3w2j5vKSRE6k7149rMGoWvWQrtlZzQ4LeqAKN8o9CPsONH_nM4CrLO/pub)) (Community Request for Proposal). The goal will be to have the community not only do the dev, but help drive requirements. We are looking forward to getting the community involved.
If interested: Please send your proposals to [email protected] with the subject line: New Arena -CRFP — 'Your TC Handle'
Please use this thread for any queries: http://apps.topcoder.com/forums/?module=Thread&threadID=922202
208.
Roma launch vehicle gate driver IC Roma announced that developed a vehicle with insulation device gate driver IC BM6103FV-C, from June 2012 to start sample shipments. The product through on-chip embedded transformer, ensure that the 2500Vrms the insulation.<br />
<img src="http://i.gasgoo.com/upload/ubb/201251792520.jpg" alt="reliabletop" width="236" height="179" hspace="12" align="left" />Overall dimensions of only 6.50mm × 8.10mm × 2.01mm (SSOP-B20W). According to Roma, with the gate driver IC and opto-coupler combination, the new product allows package size reduced by about 50%. Moreover, compared with the other with insulating function of the gate driver IC, package size of the industry's smallest (Roma). In addition, the power consumption of the new product is very small, Roma, said that when using existing External optocoupler of <a href="http://www.reliabletop.com"><strong>obd2</strong></a>, power consumption can be slashed to about 1/4. The product can be used to drive silicon (Si) power MOS...
Roma launch vehicle gate driver IC
209.
Enough of LeetCode Cheating – Similarity Might Be of Some Help! https://www.similarity.in/
Cheating in live contests is getting out of hand, and it’s frustrating for those who put in real effort. To tackle this, we launched Similarity, a platform that detects and flags identical or highly similar code submissions.
In just **24 hours**, we received **9000+** website visits, showing how big of an issue this is in the community!
We’d love for LeetCode redditors to try out the platform and share their experience. Any suggestions, feedback, or thoughts—positive or negative—are highly appreciated!
Check out my LinkedIn post about the project:
https://www.linkedin.com/posts/vyom-goyal-09ab5b246_leetcode-cp-codechef-activity-7309554874973634560-iwhA?utm_source=share&utm_medium=member_desktop&rcm=ACoAAD0KA7YBVgX3HRBzcJc8GTGpIpRlTqxGmVk
Let’s work together to bring fairness back to LeetCode contests!
#LeetCode #CompetitiveProgramming #CodePlagiarism #FairPlay #Similarity
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