Hi, Codeforces!

I welcome everyone to participate in Codeforces Round 941 (Div. 1) and Codeforces Round 941 (Div. 2), which will start on Apr/27/2024 17:35 (Moscow time).

Both divisions will be given 6 problems and 2 hours to solve them.

One of the problems was also used in the Yandex Cup finals, which was authored by tourist, so if you participated in the Yandex Cup finals or know the problems, please refrain from participating. All other problems were created and prepared by me.

I would like to thank:

• tourist for creating and preparing one of the problems
• 244mhq for coordinating the round and translating statements to Russian
• AlexanderL, Brovko, errorgorn, espr1t, ezdp, ezraft, IgorI, Java, Kaitokid, kotatsugame, Leonardo16, MJavad, ScarletS, Thost, tourist, and Um_nik for testing the round
• and of course, MikeMirzayanov, for the Codeforces and Polygon platforms

Good luck to all the participants!

Score distribution:

Division 1: 500 — 1250 — 1500 — 2000 — 2500 — 3500

Division 2: 500 — 1000 — 1500 — 2000 — 2250 — 3000

Update: Editorial is up

Congratulations to the winners!

Div. 1:

1. jiangly
2. conqueror_of_tourist
3. satoshi
4. tatyam
5. bruhopen

Div. 2:

1. Chengxixi
2. SlhShn
3. SlavicC
4. awooga
5. zyh_helen

Hello Codeforces!

We're glad to invite everyone to participate in Codeforces Round 940 (Div. 2) and CodeCraft-23, which will start on Apr/21/2024 17:35 (Moscow time). The contest will be rated for all the Div. 2 participants (Rating < 2100).

The Programming Club at IIIT-H organizes this event as a part of our techno-cultural fest Felicity @ IIIT Hyderabad.

You will have 6 problems to solve in the duration of 2 hours 2 hours and 15 minutes. One of the problems is divided into 2 subtasks. Do ensure you read all of the problems!

There have been a bunch of people that have helped us in making this contest a (hopefully) great one!

• ScarletS and KAN for their wonderful coordination.
• Alexdat2000 for translating the problem statements to Russian.
• akcube, fangahawk, GenghizKhan, JadeReaper, kevaljain, keyurchd_11, lezirtin, ppt1524, Prakul_Agrawal, SilverTongue1729, shakr, TheRaja who helped with brainstorming problem ideas and preparing them.
• A_G, dorijanlendvaj, Andreasyan, MridulAhi, codelegend, prvocislo, satyam343, shiven, mwen, JagguBandar, fishy15, islingr, nor, golions, WAtoAC2001, hackerbhaiya, carnation13, Murinho, AbhijnanVegi, freaksier for testing the round, and giving useful advice regarding problem preparation to make the contest better.
• And MikeMirzayanov for the amazing platforms, Codeforces and Polygon, which has made contest preparation an even greater experience.

Score Distribution: $$$500 - 1000 - 1500 - 1750 - 2250 - (2250 + 1250)$$$

Hope you enjoy the problems!

UPD: The editorial can be found here.

UPD: The Winners

Official

1. Alphaqwq_
2. misfits
3. Monkey1ng
4. Nanani_fan
5. lmq3z

Unofficial

1. BurnedChicken
2. maspy
3. kotatsugame
4. zdc123456
5. zjy2008

Hello Codeforces!

The 2023 ICPC World Finals Luxor will begin on April 18, 2024 at 10:00 UTC. This time, we have a double World Finals. You can distinguish them by colors: blue (fish emoji) and green (crocodile). Join us on the live broadcast for this awesome double event of the year in competitive programming; commentators will include ecnerwala, SecondThread, Egor, and more!

ICPC World Finals Luxor is hosted by The Arab Academy for Science, Technology, & Maritime Transport (AASTMT), the ICPC World Finalist teams for two seasons will compete for World Championship awards, prizes, and bragging rights. More than 130 teams of each season represent the best of great universities of eight ICPC regions.

Teams qualified to ICPC WF Luxor:

• Official list — select region
• Non-official list with CF rating: 46 47

Some useful links:

• Official website of the ICPC
• Official ICPC WF Luxor website
• Schedule of Events
• Live broadcast
• Photo Gallery
• Mirrow Contest
• ICPC World Finals Mirror (ksun48 + Petr + tourist)
• Luxor brochure

Scoreboards:

All available broadcasts:

Also, you can observe teams' monitors and web cameras on the separate broadcast. Sent team's hashtag to the chat to see your favorite! All hashtags for both seasons were collected in this list

We wish good luck to all competing teams to have a great time spending, and to do the best to get amazing results!

(I'm too lazy to write a post so I copied last year's, thanks pooty)

Hello, Codeforces community!

We are happy to invite you to participate in National University of Singapore (NUS) CS3233 Final Team Contest 2024 Mirror on Monday, April 15, 2024, at 09:15 UTC. CS3233 is a course offered by NUS to prepare students in competitive problem solving.

The contest is unofficial and will be held in Codeforces Gym. Standard ICPC rules (Unrated, ICPC Rules, Teams Preferred) apply. The contest is unrated. Note the unusual starting time.

The problems are written and prepared by user202729, rama_pang, tzaph_, benson1029, HuaJun, and feeder1.

We would also like to thank:

• Prof. Steven Halim for coordinating and teaching the CS3233 course;
• benson1029 and HuaJun as teaching assistants;
• stack.py (Pyqe, hocky, faustaadp), and Berted for testing the contest;
• errorgorn for existing;
• the Kattis team for the platform used in the CS3233 course and in the official contest;
• Codeforces Headquarters for letting us announce on the main page; and finally
• MikeMirzayanov for the amazing Codeforces and Polygon platform!

The contest will last for 5 hours and consist of 13 problems. While it is preferred to participate in a team, individual participation is also allowed.

The problems themselves may be quite standard as they are targeted toward those who have just learned competitive problem solving. However, we have also included a few challenging problems for stronger teams, such as ex-IOI or ICPC participants taking part in the course as well. So, the participants can expect a good mix of problems of varying difficulty levels, that we hope can be educational!

We hope you will enjoy and have fun in the contest. Good luck!

UPD: The contest is over! Here is the editorial.

Ciallo, codeforces～(∠・ω< )⌒☆

We are pleased to invite you to participate in Codeforces Round 939 (Div. 2), which will start on Apr/13/2024 17:35 (Moscow time).

The problems are from Otomachi_Una and me.

This round will be rated for participants whose rating is below 2100. Participants with higher ratings may participate out of the competition.

You will be given 6 problems and 2 hours to solve them. We hope you find them interesting.

We would like to thank:

• DaiRuiChen007 and lichenghan for helping prepare this contest.
• IgorI and irkstepanov for coordinating the round.
• A_G, NemanjaSo2005, yeminghan, lunchbox, Andreasyan, lsantire, RabbieWjy, yurongyi0504, KKT_89, MinaRagy06, carnation13, Romakolesn, blitztage, qsc114, Adam_GS, Evarine and htetgm for testing.
• MikeMirzayanov for Codeforces and Polygon platforms.

Score distribution: $$$500-750-1500-1750-(1500+750)-2500$$$

Good luck on the round and high rankings to everyone!

UPD: Editorial out.

UPD: the winners

Photo of authors (unfortunately, I can't come, so my profile is shown in the picture):

UPD: The rating changes for Educational Codeforces Round 164 will be applied after this round.

Hello Codeforces!

The series of Educational Rounds continues thanks to the support of the Neapolis University Pafos.

On Apr/12/2024 17:35 (Moscow time) Educational Codeforces Round 164 (Rated for Div. 2) will start.

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 adedalic Dalabaev, Ivan BledDest Androsov, Maksim Neon Mescheryakov, Roman Roms Glazov and me. Also, huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

Big thanks to the tester shnirelman for his valuable advice and suggestions!

Good luck to all the participants!

UPD: Editorial is out

Hello! Codeforces Round 938 (Div. 3) will start at Apr/08/2024 17:35 (Moscow time). You will be offered 6-8 problems with expected difficulties to compose an interesting competition for participants with ratings up to 1600. However, all of you who wish to take part and have a rating of 1600 or higher, can register for the round unofficially.

The round will be hosted by rules of educational rounds (extended ICPC). Thus, solutions will be judged on preliminary tests during the round, and after the round, it will be a 12-hour phase of open hacks.

You will be given 6-8 problems and 2 hours and 15 minutes to solve them.

Note that the penalty for the wrong submission in this round is 10 minutes.

Remember that only the trusted participants of the third division will be included in the official standings table. As it is written by link, this is a compulsory measure for combating unsporting behavior. To qualify as a trusted participant of the third division, you must:

• take part in at least five rated rounds (and solve at least one problem in each of them)
• do not have a point of 1900 or higher in the rating.

Regardless of whether you are a trusted participant of the third division or not, if your rating is less than 1600, then the round will be rated for you.

Problems have been created and written by our team: mainyutin, VManoshin, ssor96 and ZergTricky.

We would like to thank:

1. Vladosiya for help with ideas and great coordination of the round;

2. FairyWinx, sevlll777 for red testing;

3. ace5, Nickir, KwisatzCoderach, vladmart for yellow testing;

4. natalina for blue testing;

5. bitthal04 for cyan testing;

6. Alequisk, Mohamed_Hesham for green testing;

7. MikeMirzayanov for Polygon and Codeforces platforms.

Good luck!

UPD: There was an issue with the validation of hacks for problem G, but it has now been resolved. All successful hacks will be rejudged. Pretests were not affected by the issue and remain unchanged.

UPD2: Editorial is out.

Xin chào Codeforces (・ω・)ﾉ

We are pleased to announce the resumption of the Global Rounds. Thanks to XTX Markets for supporting the initiative! In 2024, we will hold 4 such rounds. The series results will take into account the best 3 participations out of 4.

On Apr/06/2024 17:35 (Moscow time) we will host Codeforces Global Round 25.

Codeforces Global Round 25 marks the first round in the 2024 series of Codeforces Global Rounds. These rounds are open and rated for everyone.

The prizes for this round are as follows:

• The top 30 participants will receive a t-shirt.
• 20 t-shirts will be randomly distributed among participants ranked between 31 and 500, inclusive.

The prizes for the 4-round series in 2024:

• In each round, the top-100 participants get points according to the table.
• A participant's final score will be the sum of the points they earned in their 3 highest-placing rounds.
• The top 20 participants across the series will receive sweatshirts and placement certificates.

We extend our gratitude to XTX Markets for supporting the global rounds initiative in 2024!

The problems were all marinated and cooked by MofK and Kuroni.

Our sincerest gratitudes go to:

• errorgorn for being the 🥶 and 😭 coordinator, and TheScrasse for being the 🧌 coordinator.
• xuanquang1999, gamegame, zeena., lanhf, Sana, trungnotchung, lmcutezzz, mir, imsuck12, Saacoota, htetgm, kodomo_tachi, shine_, uocgimauxam, Pemguimn, Bananabread, hphuong, DeMen100ns, Kriz_Wu, milind0110, YangJackie, Vladithur, Ann, Endagorion, richzli, BucketPotato, and FireGhost for testing and ensuring the balance of the round.
• Alexdat2000 for translating the statements to Russian.
• And of course, MikeMirzayanov for Codeforces and Polygon.

Round Information:

• Duration: $$$3$$$ hours.
• Number of problems: $$$9$$$ problems.
• Score distribution: $$$500 - 1000 - 1500 - 1750 - 2250 - 2750 - 3250 - 3500 - 4000$$$.

A tiny bit of personal note at the end, this is our first round on Codeforces in 3 years, and it feels a bit nostalgic to be back here again :) We eagerly anticipate your participation and let's all make it an awesome contest together!

UPD: Added score distribution.

UPD: The round has concluded. Congratulations to the winners!

1. Geothermal
2. ecnerwala
3. Um_nik
4. maroonrk
5. jqdai0815
6. Benq
7. hos.lyric
8. antontrygubO_o
9. cmll02
10. AlternatingCurrent

Tutorial can be found here, and playlist of songs used in the problem statements can be found here.

Hello, April Fools lovers Codeforces!

We, AlperenT, flamestorm, ToxicPie9, and willy108, would like to invite everyone on Codeforces to April Fools Day Contest 2024! The 12th April Fools Day Contest will take place on Apr/01/2024 17:35 (Moscow time). This is a joke competition in which solving the problem is often easier than figuring out what the actual task is.

In this round, you will be given $$$n$$$ cool bugaboos where $$$-1 \le n \le \textbf{[REDACTED]}$$$ and 2 hours to solve them. The contest will use extended ICPC rules (no hacks, the standings are decided by the number of solved problems and penalty time earned on them). You can submit solutions in any language allowed by Codeforces, unless the problem says otherwise.

Please note that the round is unrated and that the penalty for a wrong submission is 10 minutes.

To get an idea of what the contest will look like, you can check out the contests of the past years: 2012, 2013, 2014, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023. (It has been 12 years since the first April Fools Day Contest, thank you Nickolas!)

Please do not send any clarification requests in the contest, as we definitely will not be sending funny responses like we did last year.

Good luck, and have fun!

UPD: Editorial is released!

UPD: Congrats to the winners:

1. tiger2005
2. emthrm
3. Enchom
4. arvindf232
5. KumaTachiRen

And the first solves on each problem:

• A: InternetPerson10
• B: Mr_Buffon
• C: Thienu
• D: moraprex
• E: BalintR
• F: SanguineChameleon
• G: 7_divided_by_3
• H: Owmicron
• I: JJJiang.is.MyGO
• J: Joshc