Codeforces: Results of 2023 [Annual Report] Hello, Codeforces. Let's recall 2023, shall we? In this post, I want to summarize this year. You know, a lot of terrible things happen in the world, and personally, this year was the hardest and most sorrowful for me. But today, we'll remember something else. We'll remember what this year was like for Codeforces. Recently, Codeforces turned 14 years old. Not bad, right? And for many years now, when asked "What is Codeforces?" the first thing I say is — it's a community! [cut]<br/> #### Personal Thanks! On behalf of the community (and myself), I say thank you to everyone who tries, helps, and makes efforts to keep the community alive. Thank you to the developers! Although I continue to engage in development and other technical activities, I'm glad that these guys made an effort and improved the platform: [user:geranazavr555,2024-02-04], [user:unreal.eugene,2024-02-04], [user:vbandurin,2024-02-04], [user:ChurakovaAlexandra,2024-02-04], [user:medvezhonokok,2024-02-04]...

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Osijek Competitive Programming Camp 2023 winter — wrap Hi everyone! <center><a href="https://ocpc.mathos.unios.hr"><img src="https://ocpc.mathos.unios.hr/images/ocpc.svg" height="100px"></a></center> <center> <b>Sponsored by</b><br> <a href="https://www.janestreet.com/join-jane-street/open-roles/?type=students-and-new-grads&location=london"> <img src="/predownloaded/ee/f2/eef26616a3661c658d1545f18ed21fabb14d5871.svg" height="50px" style="margin: 5px 5px 5px 5px;"> </a> <a href="https://www.think-cell.com/osijek2023"><img src="/predownloaded/97/88/97887beeb75a4601259414b36ecee0160c29d027.svg" height="40px" style="margin: 5px 5px 5px 5px;"></a> <a href="https://pinely.com/"> <img src="/predownloaded/0a/0f/0a0f3f67435d1f6e467bc7203d4a2090ba8f92cc.svg" height="50px" style="margin: 5px 5px 5px 5px;"> </a> </center> The [Osijek competitive programming camp](https://ocpc.mathos.unios.hr) (also see the [announcement](https://codeforces.me/blog/entry/110945) on Codeforces) just concluded last Sunday, on February 26, and I'd lik...

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Codeforces: Results of 2017 <img src="/predownloaded/e4/09/e40915ee54c5991b91098756a90270d94be893b3.jpg"/> Happy New Year, Codeforces! I hasten to wish the whole community (and including me) correct programs, sudden insights, beautiful ideas and interesting problems! I hope that you have met the new year at least as fun as I am. Have you had enough sleep after New Year's Eve? This year, the traditional post summarizing the past year, I sat down to write only on January 1, 2018. I hope that I will not have to sum up the whole year. This post is important to me, since it draws a line to all the work done by the Codeforces team and the entire community in 2017. Many thanks to the team: all of the achievements listed below are the result of joint efforts. We did an excellent job! The community must know its heroes. In 2017, [user:MikeMirzayanov,2018-01-02], [user:KAN,2018-01-02] (problem coordinator), ~gritukan,2018-01-02 (second problem coordinator), ~netman,2018-01-02 (ex-second problem coordinator), ~k...

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Codeforces Month of Blog Posts Results One and a half months ago [I proposed a challenge](https://codeforces.me/blog/entry/110840) to every one of you to get something from your drafts or from your head and actually write a blog post about it. I got a bunch of submissions, and you can find the links to all of them throughout this blog post (I was actually surprised that all entries were meaningful and interesting, so I definitely recommend checking them out). If you submitted an entry and I didn't mention it here, it is not purposeful! Indicate it via a direct message and I will include it here. It was just a bit hard to keep track of all submissions. I went through all the submissions. Some of them were very complicated, and I tried my best to get the overall idea but I will need to come back to dive deeper into some technical proofs. However, I believe that these technicalities that I glanced through do not affect my decisions. We are ready to present the winners! Regarding the first place, there was no doubt in my...

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Coronavirus — Overcome the Psychological Stress by Coding My video on the topic: [Shameless Self-Promotion](https://www.youtube.com/watch?v=CFagJwWW7ys) Have you ever noticed how disasters have a weird way of making things better, once the initial problem is contained? Yes, the virus is unpredictable, has deadly potential, and should be of great concern to just about every human on the planet. So, what could possibly be a positive consequence of a life-threatening disease? #### _**1. Code (and live) for the present, not for that offer**_ Yes, these are not the best of times, but a time to reflect on who we are and what is most important in life. For some countries, economy is at risk. But most of Software Engineer jobs give you the opportunity to work remote/from home. Either you have or not a job at the moment, you are not so pressured by this thought anymore. Maybe you come to the conclusion programming is not what you want to do in life anymore. Maybe it's photography, cooking or pottery (Brad Pitt pff..). Or maybe th...

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Standings in AtCoder Virtual Participation While using the virtual participation tool on AtCoder, the "Standings" page shows the result of the contest as of the end of the competition. This means there isn't a way to view the standings as of the current time in your virtual contest (i.e., when I'm one hour into my virtual participation I would want the standings to display the results from submissions made in the first hour of the contest). This prevents me from practicing using the scoreboard to inform my strategy. The "Virtual Standings" tab does adjust to the time of the virtual contest, but there are usually too few participants for this page to provide much useful information. Right now, the best solution I know of is to use CLIST, which does support viewing scoreboards partway through a contest, by just scrolling to the current time in my VC whenever I want to check the scoreboard, but this isn't an ideal solution because it involves using an external site and requires me to manually select the current time in my virt...

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I have solved problems on Codeforces for 500 days in a row It's been a while since I started my journey into competitive programming and in this year and (almost) a half I would say that I learned a bit not only about problem solving but also about myself, so I wanted to share my reflections on some mental aspects of practicing competitive programming hoping they can help someone else. Please note that these reflections are merely personal and mostly stem from personal experience, if you disagree with something I would like to know your point of view! I would also like to thank [user:Intellegent,2025-12-08], [user:turska,2025-12-08] and [user:LMeyling,2025-12-08] for proofreading.  #### Some background I used to do math olympiads for 8 years before starting university, in hindsight I did not really like it that much since I never practiced on my own and would've rather played League of Legends / Minecraft / VALORANT or whatever game I was obsessed at the time. ...

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ACPC Story 5# "I want to present an objective perspective on why the competition raises concerns, rather than writing a narrative or story. This is based on being a community leader for a year and contestant for 3 years now. 1. Inconsistent and Informal Payment Structure : Payments are handled through external channels, not the official platform. **Some teams pay 25,000 EGP per person (officially qualified), others 50,000 EGP per person (unofficially).** This year for the first time after deadlines, an additional 10,000 EGP per person is charged—an unreasonable variation. 2. Mandatory and Overpriced Accommodation Bundled with Fees : Participants **must pay** fixed accommodation bundled with registration, costing 25,000 EGP per Egyptian student—roughly a semester’s tuition—regardless of personal circumstances. Many could find alternatives for 1% of the cost, yet teams may still pay the full amount even if a member cannot attend, making the policy highly unreasonable and wealth-dependent. 3...

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IICPC Global Quantfest 2026 Hello! Registrations for **IICPC Global Quantfest 2026** are now open. This is 2nd Global IICPC Examination, bringing together Quantitative Finance, Probability, and Competitive Programming, built on IICPC's rich legacy of nurturing top talent. **About IICPC Quantfest** IICPC (Intercollegiate Informatic and Competitive Programming Camp) is a student-led initiative dedicated to advancing competitive programming and quantitative problem solving for the globe. Over the past few years, IICPC has organized bootcamps, contests , recruitment examinations, and educational programs connecting thousands of students with industry and academia. Quantfest is a global quantitative problem-solving festival where the brightest analytical minds tackle challenges inspired by real-world trading and quantitative roles. This year, we are opening participation to international students from 50+ countries. **Registrations go live on July 20, and remain open till August 20.** There is no partic...

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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...

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Psychology for programmers I I always wanted to write article about what I have learned in psychology, and how it relates to programming. It was hard to come up with single article, so I decided that I will write multiple unrelated blogs. The first post is about **Rating Anxiety**, there have been no scientific studies about this phenomena to my knowledge, but from self-reports of competition programmers, I conclude it exists, and I think a lot coders develop it to certain degree and certain peronalities are more prone for the developement. Rating anxiety(RA) is when you feel bad about losing rating(TopCoder or CodeForces) and as a consequence of that you either **skip competition** or are nervous and under pressure because of that. In practice this pressure leads to poor performance(thrugh means I will describe in other post), and individual might gain better results if he gets rid of rating anxiety. If your in-contest and ot-contest performance differs somehow, it might be sign of RA. If you feel intese jo...

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Impulse — ICPC Style Competitive Programming Contest | ₹33,000 Prize Pool Impulse &mdash; ICPC Style Competitive Programming Contest ============================================================================================== Hello, Codeforces community! We invite you to **Impulse**, an ICPC-style team contest by Scaler School of Technology — focused on teamwork, speed, and algorithmic problem solving. Meet the Team ------------- **Problem Setters & testers :** [user:jonseagull,2026-04-24] [user:jadoocoder,2026-04-24] [user:Subhankar744,2026-04-24] [user:Prabhdeep-24,2026-04-25] Event Details ------------- **Online Qualifiers** - 1st May 2026, 9:00 PM – 12:00 AM (IST), Codeforces **Offline Finals** - 17th May 2026, 2:00 PM – 7:00 PM (IST), @ Scaler School of Technology, Bengaluru Top teams from the online round qualify for finals. **Team Details** - Team Size: 2–3 members **Prizes** - ₹15,000 | ₹11,000 | ₹7,000 **Registration:** https://unstop.com/competitions/1669639 **Whatsapp Group Link:** https://cha...

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NowCoder Summer Multi-School Training Camp 2025 Hello, Codeforces! As the official team of NowCoder (China's leading programming competition platform), we are pleased to introduce the 2025 NowCoder Summer Multi-School Training Camp! This annual event has been running for eight years. Since the summer of 2018, we have collaborated with top competitors from algorithmic competitions such as ICPC, NOI, and IOI, aiming to enhance participants' programming skills through competitions, lectures, and exchanges, and to prepare for upcoming competitions like ICPC and CCPC in the second half of the year; simultaneously, we seek to foster learning and exchange among university training teams worldwide. <center> <h2 style="border-bottom: 1px solid #000;">Details</h2> </center> 1. **Schedule**. Consistent with last year, this year's training camp will consist of ten ICPC-style competitions, starting on [Tuesday, 15 July 2025<sup title="timezone offset" style="font-size:8px;" data-immersive-translate-walked="24cdac9c-eeae-41da-aef2-9dcf...

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CF X-Users : Website For X-Users ! ### WEBSITE DOWN #### UPDATE : 27 AUG 2020. 0. As you all might have noticed on the [Leaderboard](https://cf-x-user.herokuapp.com/leaderboards), we have people with <strong>times_caught</strong> more than $4$. I wonder when will they get a ban from Codeforces. 1. Added a new feature for people to **report X-Users**, the solutions which were mangled or clever enough to bypass MOSS. These things go under manual validation for now, but if confirmed it will give +100 X-Rating Gain to the X-User, also this incident would be mentioned on their profile as "<strong>Notoriety</strong>". 2. I have added an **Appeal** section. People who are badly affected or people who think that someone is impersonating them can add an appeal. i would remove those X-Users but for X-Users with <strong>times_caught</strong> $>$ $2$, appeal won't help much. But i would see if anything can be done. ### Introduction <strong>What is a X-User?</strong> Its just a person, who's solution gets s...

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ICPC Preliminary Rounds Should Be Held at Examination Centers The rapid growth of AI has made it increasingly difficult to ensure fair competition in online programming contests. While most participants compete honestly, the availability of powerful AI tools creates opportunities for unfair advantages during ICPC preliminary rounds. To preserve the integrity of the competition, ICPC preliminaries should be conducted at designated examination centers such as IITs, NITs, and IIITs. A supervised environment would significantly reduce the possibility of AI-assisted problem solving and ensure that qualification is based on genuine programming ability. ICPC is meant to identify the best problem solvers, not the best users of external tools. As AI continues to advance, moving preliminary rounds to supervised centers would help maintain the credibility, fairness, and prestige of the competition.

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Invitation to CodeRed 2026  # Hello Codeforces! Ready for a high-intensity ICPC-style battle? We are excited to announce **CodeRed**, one of the flagship competitive programming events of **Aparoksha**, the annual tech fest of the **Indian Institute of Information Technology Allahabad**. If team strategy, whiteboard arguments, last-minute hacks, and the sweet sound of *Accepted* excite you, this contest is for you. --- ## Contest Details **Date:** 12 April 2026 **Time:** 5:00 PM – 8:00 PM (IST) ##### **Contest Link** Kindly use the invitation link below to register for the contest: https://codeforces.me/contestInvitation/baac2882fdbed30238dedbb68160772bfcde6bff ##### **Finals (Offline Round)** Top performing teams from the **online round** will be invited to the **offline finals at IIIT Allahabad**. The finals will be conducted **on campus**, where selected teams will compete in an intense **ICPC-style s...

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Google Code Jam to I/O for Women registration is open for the single online round on Saturday, February 15 Code Jam to I/O for Women 2020 registration is open! Back for its seventh year, Code Jam to I/O for Women is an online coding competition that aims to bring more women (external) from around the globe to Google I/O. On Saturday, February 15, the single online-round will test participants' programming skills through a series of intriguing algorithmic challenges. The top 150 participants will receive a ticket to Google I/O along with a travel reimbursement. Do you like solving fun, challenging problems? Then try your hand at Code Jam to I/O for Women, our coding competition bringing women from around the globe together in a single online round on Saturday, February 15. Register today→ [g.co/codejamio](https://g.co/codejamio).

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Beta Round #4 — csacademy.com Hello, Codeforces! We are happy to announce that we're going to host a new contest at [csacademy.com](http://csacademy.com). Once again we'd like to thank all our users for the great feedback they provide. We try to listen to your advice and improve our platform with each competition. Our [Beta Round #4](https://csacademy.com/contest/beta-round-4/) will take place on [Tuesday, Apr/26/2016 16:00 (UTC)](http://www.timeanddate.com/worldclock/fixedtime.html?msg=CSAcademy+Beta+Round+4&iso=20160426T16&p1=1440&ah=2). If you want to take part in this round you need to [register](https://csacademy.com/contest/beta-round-4/) before the contest begins. You can access the chat room for this round [here](https://csacademy.com/contest/beta-round-4/#chat) (login required). Initially we were planning on having two divisions starting with this round. After taking a closer look at the rankings we decided it's too early to separate our users. So this round will be a Div1 + Div2, with 3 easy tasks a...

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Invitation to an informal competition I will be hosting a CP competition for my colleagues at work today (April 10) at 17:00 UTC, and I was wondering if anyone here from Codeforces would be interested in joining. It would be fun to have some external participants as a reference. The six problems are easy to medium. I will host the competition on LightOJ, so an account there is needed to participate. If you are interested, please send me a message with your LightOJ nickname. Many thanks to [user:vgtcross,2023-04-10] and [user:PiejanVDC,2023-04-10] for reviewing the problems!

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How to write PC^2 special judge for precision checkings? We are going to organize a competition, but we cannot find any resources that help us to write external validator to check if the output is close enough to the expected answer. Can someone provide us some working validator files or give us some idea on how to work? Any testlib solution will be appreciated.

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A Sincere Apology and Humble Request for Reconsideration of My Codeforces Account Dear @MikeMirzayanov and the Codeforces Administration, I am writing this blog with sincere regret regarding my mistake during a recent Codeforces contest, which resulted in the disabling of my account, @kr_madhukar. I sincerely apologize to the Codeforces administration and the entire community for using AI assistance during a contest. I understand that this violated the contest rules and was unfair to participants who competed honestly. I take full responsibility for my actions, and I do not wish to make excuses or justify my decision. After reflecting on this incident, I recognize that competitive programming is not simply about ratings, rankings, or the number of problems solved. It is about independent thinking, continuous learning, fair competition, and respect for the rules that make the platform valuable to everyone. Codeforces has been an important part of my learning journey as a student. I have invested considerable time in practicing algorithms, solving problems...

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CodeWars 2015 (Duplicate) ACM, Bits Pilani Hyderabad campus is organizing the their flagship coding competition, CodeWars. This year's problem setters include [user:pranet,2015-10-04], [user:venkyb,2015-10-04], [user:sabarinath,2015-10-04], [user:lone_rider,2015-10-04] and [user:yashraj2604,2015-10-04]. It will be a 3-hour ICPC style contest with 5 problems and binary scoring. It is an individual contest(Teams not allowed). The contest will be held on Hackerrank.The contest link will be updated soon. The contest starts at 21:00(IST) on 5th October, 2015. [time](http://www.timeanddate.com/worldclock/fixedtime.html?msg=CodeWars+2015&iso=20151005T21&p1=54&ah=3) **Contest link** : [link](https://www.hackerrank.com/codewars-2015-1) **UPD 1** : The contest is about to start in an hour. **UPD 2** : The problems have been served. The fifth problem will be released within half an hour. Sorry for the inconvenience caused. **UPD 3** : The contest is over. I hope you liked the problems. We'd like to thank...

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Request for Account Review and Restoration Dear [ MikeMirzayanov] and Codeforces Administration, ========================================================= I am writing to sincerely apologize and request a manual review of my disabled account, [karthikeya_rk]. My account was recently disabled due to a violation regarding AI usage. I fully acknowledge that using AI assistants to generate code solutions during live contests goes against the core values of fair competition on Codeforces. I deeply regret making this mistake and taking an unfair shortcut.`` Codeforces has always been an invaluable platform for me to learn, improve my problem-solving skills, and be part of the competitive programming community. Losing access to my account has made me realize the importance of academic integrity and honest practice. If given a second chance, I promise to strictly adhere to all platform rules, solve every problem completely on my own, and never use AI tools or external assistance during active rounds again. I am entirely willing to...

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Why do users make multiple accounts? I will attempt to explain why I think people do this, and hopefully start a serious examination of how to deal with the problem... ~~~~~ struct Warning{ long long story; }; ~~~~~ Label: Meet Bob. Bob has always been a pretty bright individual. Deciding that he should use his intelligence for good, Bob decided to put his skills to the test. As Bob knows, people use computers for programming. Because Bob owns a computer, he figures he must be a programmer as well. So Bob decided he was going to create the best game ever &mdash; one that would inspire a generation of children to waste their lives chasing pixels &mdash; solely with the power of his mind. Absolutely sure of how to continue, Bob promptly opened up the command prompt. This made sense to Bob because he once saw a monospaced screen in a movie where some dude hacked the government in 90 seconds. He proceeded to type in his masterpiece: ~~~~~ open a new window make the background look like trees put a guy w...

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Request for Review of My Disabled Account Hello Codeforces community, My Codeforces account, logicflow, was recently disabled. I am writing to respectfully request a review of my case by the Codeforces Administration. I would like to be honest about my conduct during the recent contest. I used AI during the contest to obtain assistance with problem solutions. At the time, I did not properly consider the seriousness of this action and its implications for fair competition. I now understand that this violated the contest rules, and I sincerely apologize. I take responsibility for my mistake. I understand that contests must be fair to all participants, and I regret not following the rules as I should have. I am not asking the administration to ignore the rules or overlook my actions. I am respectfully requesting that my case be reviewed and, if possible, that I be given another opportunity to participate in the future. Codeforces has been an important part of my programming journey. I regularly use the platform to ...

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A Recap of My First Year in CodeForces Hello all on Codeforces! ------------------ It’s been just over a full year since I created my Codeforces account. Since then a lot has happened on my Codeforces journey so far. With everything that’s happened I want to look back at how I got to my current point, share what I learned in the process, recap some of my best moments, and laugh at whatever I was thinking on a few of these contests, because a lot happened. The only issue is that there’s no way I’m going to detail all **60** contests I took part in 2022. Instead I’ve chosen to “award” the 9 most memorable contests, wheter it be because I did exceedingly well or self destructed in almost hilarious fashion. A few notes before I begin: No full solutions for any problems are shown in this post but there are code snippets and discussions that are spoilers for these problems. I apologize in advance. ### First Contest &mdash; [Hello 2022](https://codeforces.me/contest/1621) This was the first contest held in 2022, ...

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