By Little09, 43 hours ago, In English

Hello, Codeforces!

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 Dec/19/2024 17:35 (Moscow time) we will host Codeforces Global Round 28.

Codeforces Global Round 28 marks the fourth 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 9 problems were authored by our 4 authors: JoesSR, cmk666, wsyear and Little09.

We would also like to thank:

Round Information:

  • Duration: 180 minutes.
  • Number of problems: 9 problems with 1 subtask.
  • Score distribution: $$$ 250 - 500 - 1000 - 1250 - 1750 - 2000 - 2250 - 2750 - (3000 + 3000) $$$.

We eagerly anticipate your participation!

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By cry, 12 days ago, In English

Hello Cowodeforces :D

Art by chromate00

vgoofficial, Lilypad and I are very to invite you to participate in Codeforces Round 993 (Div. 4), which will start on Dec/15/2024 17:35 (Moscow time). There will be $$$8$$$ problems, with one split into two subtasks, to be solved in $$$2$$$ hours and $$$15$$$ minutes. Participate or you'll have to wait another millennium for a Div. 4 round.

The format of the event will be identical to Div. 3 rounds:

  • ICPC rules with a penalty of 10 minutes for an incorrect submission;
  • 12-hour phase of open hacks after the end of the round (hacks do not give additional points)
  • after the end of the open hacking phase, all solutions will be tested on the updated set of tests, and the ratings recalculated
  • by default, only "trusted" participants are shown in the results table (but the rating will be recalculated for all with initial ratings less than 1400 or you are an unrated participant/newcomer).

We urge participants whose rating is 1400+ not to register new accounts for the purpose of narcissism but to take part unofficially. Please do not spoil the contest for the official participants.

Only trusted participants of the fourth division will be included in the official standings table. This is a forced measure for combating unsporting behavior. To qualify as a trusted participant of the fourth 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 1400 or higher in the rating.

Regardless of whether you are a trusted participant of the fourth division or not, if your rating is less than 1400 (or you are a newcomer/unrated), you may choose to participate rated or unrated.

We want to express overwhelming gratitude to the following orzosities for making the contest possible:

UPD: Editorial

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By Igor_Parfenov, history, 12 days ago, In English

Hello!

On Dec/08/2024 17:35 (Moscow time) we will host Codeforces Round 992 (Div. 2).

The problems were written and prepared by Igor_Parfenov.

I would like to thank everyone who made this round possible:

This round will be rated for participants with rating lower than 2100.

You will have 2 hours to solve 6 problems.

Score distribution: 500 — 1000 — 1500 — 2000 — 2250 — 2750.

Good luck!

UPD: Editorial

UPD: Congratulations to the Winners!

Div.2:

  1. daniel6202

  2. younesg

  3. houseof

  4. HUST_USELESS

  5. FatihCihan

Div.1 + Div.2:

  1. jiangly

  2. maspy

  3. Rubikun

  4. BurnedChicken

  5. neal

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By pskobx, 2 weeks ago, translation, In English

Hello! Codeforces Round 991 (Div. 3) will start at Dec/05/2024 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. After open hacks all accepted solutions will be rejudged on successful 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: AVdovin, DanGolov, kbats183, Vladosiya and pskobx.

We would like to thank:

  1. MikeMirzayanov for Polygon and Codeforces platforms.

  2. Vladosiya for coordination.

  3. EgorUlin, qsmcgogo, molney, misorin, vladmart, Blinov_Artemii for yellow testing.

  4. snasibov05, FBI for purple testing.

  5. artcosec, Pslnd, _icy_, Gabbasov, UniversalAdmin for blue testing.

  6. dmit_brit, WahidmShafin, Osama.Rafat100 for cyan testing.

  7. Kaushal_26 for green testing.

Good luck!

UPD: Editorial is out.

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By KAN, 2 weeks ago, In English

Hi Codeforces!

On Dec/03/2024 09:25 (Moscow time) we will hold Codeforces Round 990 (Div. 1) and Codeforces Round 990 (Div. 2). Note the unusual starting time!

The harder problems of this round are based on the problems from the Final round of Yandex Cup 2024, Algorithms track, that will be held at the same time.

The problems are authored by elshiko, Flyce, MrLolthe1st, sokolow, stepanov.aa, TeaTime, Tikhon228, webmonster, 4qqqq with guest problems from myst-6, Vladithur, BledDest and me.

I'd like to thank daubi, Golovanov399, arbuzick, pperm, orz, AgafonovArtem, Qwerty1232, k1r1t0, Itsmylove1, Sofi_, and errorgorn for testing the problems, tourist for helping with the round, and MikeMirzayanov for the Polygon and Codeforces systems.

Because of official Yandex Cup Finals ends later than the round on Codeforces, the upsolving, solutions, and test cases will be closed until the end of the onsite contest, roughly 3 hours after the end of the Codeforces round. It is also forbidden to discuss the problems publicly until the end of the onsite round. Any comments here concerning the problems will be removed.

Good luck!

UPD: The contest has been delayed to make sure the online contest does not start earlier than the onsite one.

Congratulations to the winners!

Div. 1:

  1. jiangly
  2. hank55663
  3. noimi
  4. cxm1024
  5. Pyqe

Div. 2:

  1. RGB_ICPC8
  2. timer2024
  3. tietieAM
  4. ylzxxx7
  5. mion_sonozaki

UPD: You are free to discuss the problems now.

UPD: Editorial.

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By awoo, history, 3 weeks ago, translation, In English

Neapolis University Pafos

Hello Codeforces!

The series of Educational Rounds continues thanks to the support of the Neapolis University Pafos. They offer a BSc in Computer Science and AI with JetBrains Scholarships. Gain cutting-edge skills in AI and machine learning, preparing you for high-demand tech careers. Curious? Check out the CSAI curriculum now. Limited scholarships available — don't miss your chance to study in Europe for free!

On Dec/02/2024 17:35 (Moscow time) Educational Codeforces Round 172 (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 and me. Also, huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

Good luck to all the participants!

UPD: Editorial is out

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By Pyqe, 3 weeks ago, In English

Selamat pagi Codeforces!

We're going to hold The 2024 ICPC Asia Jakarta Regional Contest.

We invite you to join the online mirror contest 2024-2025 ICPC, Asia Jakarta Regional Contest (Online Mirror, Unrated, ICPC Rules, Teams Preferred) on Codeforces. It'll be held on Dec/01/2024 08:05 (Moscow time) and will last for 5 hours.

The mirror will be held using ICPC-style scoring with 10 to 13 problems. The problem statements will only be available in English. We encourage participating as a team using only one computer for coding (as in ICPC contests). The mirror will be unrated.

Some useful links:

We hope that you'll enjoy the contest. Good luck and have fun!

UPD. The mirror has ended! You can find the editorial here. The onsite scoreboard will be unfrozen after the closing ceremony. Thank you for participating and we hope that you enjoyed the problemset!

UPD2. Mistake in Problem D. Aquatic Dragon

The act of activating a shrine is supposed to be mandatory once you reach an island instead of being optional. During contest preparation, the initial problem had a statement that implies the aforementioned obligation of shrine activation, which the judges had a correct solution for (the one in the editorial). However, when rewriting the problem statement for more clarity with adjustments to the story, we ended up making it such that it's optional, without too much thought about it, thinking it's essentially still the same problem. Unfortunately, as we have recently found out after the contest, it's in fact not the same problem.

The action we're taking now is fixing the statement of the problem after the contest with the correct intended version without changing the judges' solution. We are very sorry for the inconvenience.

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By ArshiaDadras, 4 weeks ago, In English

👋 Salam, Codeforces!

We are thrilled to invite you to the Rayan Programming Contest 2024 - Selection (Codeforces Round 989, Div. 1 + Div. 2).

The Selection Round is a rated contest for Div. 1 + Div. 2, taking place on Nov/30/2024 17:35 (Moscow time). The problems for this round were crafted and prepared by ArshiaDadras, MohammadParsaElahimanesh, AmShZ, AmirrzwM, and Keshi.

The top 60 trusted participants (with a maximum of three from each country) will qualify for the onsite Final Round in Tehran, in Spring 2025. An additional quota is reserved for the host country. Hotel accommodation, local transportation, and meals will be provided to all finalists. More details about the final contest will be available on the Rayan website.

🏆 Selection Round Prizes:

  • The top 50 participants will receive T-shirts. 👕
  • Additionally, 50 random participants from ranks 51-1000 will also receive T-shirts.

🏅 Final Round Prizes:

  • 1st place: $15,000 💵
  • 2nd place: $10,000 💵
  • 3rd place: $5,000 💵
  • 4th–6th places: $2,000 each
  • 7th–10th places: $1,000 each

🙏 Special Thanks:

We would like to extend our deepest gratitude to:

📊 Score distribution: $$$500 - 750 - 1500 - 1500 - 2000 - (2000 + 2000) - (3000 + 3000) - 5000$$$

We look forward to seeing you both online and onsite!

Good Luck & Have Fun! 🎉

Note: Editorial just published here! 🚀🍿

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By tmt514, history, 4 weeks ago, In English

Hello Codeforces!

I am pleased to invite you to participate in 2024 ICPC Asia Taichung Regional Contest (Unrated, Online Mirror, ICPC Rules, Preferably Teams), which will be held on Nov/24/2024 10:05 (Moscow time). This is an online mirror contest for the 2024 ICPC Asia Taichung Regional Contest, and the official offline contest was conducted on November 17th, 2024. The duration of the contest will be 5 hours and the contest is best for teams of three people. The mirror will use the ICPC format.

The contest tasks are proposed by the task authors (baluteshih, waynetuinfor, skylinebaby,samsam2310, hank55663, ltf0501, Jeffrey, Shik, tmt514, Bangye Wu, kasuistry, and Peter Rossmanith), prepared and polished by the judge team (Regional Contest Director Ling-Ju Hung, Chief Judge Peter Rossmanith, kasuistry, Hung-Lung Wang, baluteshih, waynetuinfor, hank55663, cthbst, Sylveon, CindyLinz, marmot0814, tmt514), and tested by the tester team (olmrgcsi, oToToT, jeeeerrrpop, nikilrselvam, Vince729, applepi216). The judges appreciate the testers for their valuable feedback!

We would like to thank MikeMirzayanov for creating the greatest Codeforces platform, and many, many, many helps for making this online mirror contest possible!


This is a photo of the contest venue. Photo Credit: Prof. Jinn-Shyong Yang.

On behalf of the 2024 ICPC Asia Taichung Regional Contest Judge Team, we hope you enjoy this contest and have fun!

Of course, this contest will be unrated.

Updated: the editorial has been released! Please refer to the link in the contest's local website.

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