Hello everyone!

Soon, the Open Olympiad in Informatics will take place, which you may know from the online mirror of last year or from the rounds 345, 469, 545, 626, 707, 775. This olympiad is prepared by Moscow Olympiad Scientific Committee. Archives from previous years, problems from qualifying stages, and other information can be found on the olympiad website inf-open.ru.

The Open Olympiad consists of interesting and difficult problems proposed by our authors' team. Therefore, we decided to conduct a non-rating mirror of the Olympiad on Codeforces. The Olympiad takes place in two rounds, each consisting of 4 problems, not ordered by difficulty, and 5 hours to solve them. The difficulty of the problems is comparable to the level of Div. 1. Each problem is worth 100 points that are distributed into multiple subtasks with different constraints that allow the participant to earn partial score. Testing is done in the IOI format, where the participant receives a full testing report on all tests in the Online-subtasks during the competition. The feature of the Open Olympiad is that some problems have Offline-subtasks, the results of which will only be available after the end of the competition. Note, that you will not have access to the scoreboard during the competition.

The mirror on Codeforces will take place in Mar/07/2025 11:05 (Moscow time) и Mar/10/2025 11:05 (Moscow time).

The competition problems were created and prepared by Kapt, allvik66, stepanov.aa, Mangooste, AgafonovArtem, dyrbulshchyl, RP-1, valerikk, yunetive29, Kniaz guided by Mangooste, grphil и Helen Andreeva. Special thanks to Tikhon228 for his contribution to the preparation of the problems.

Special thanks to MikeMirzayanov for the codeforces and polygon systems, which were used in preparing the problems for this Olympiad.

Many thanks to the Olympiad testers: Ormlis, isaf27, allvik66, AgafonovArtem, RP-1, Qwerty1232, kostylevGO, katyaporay, FairyWinx, a.stepanov281005, EgorUlin, pakhomovee, ArtAlex, Sweezy, Be_dos, valerikk, alexsushin, Dart-Xeyter, yunetive29, AndreyPavlov, Mikhango, v0s7er.

Good luck!

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 geeks veterans 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) and Pinely (HFT company powered by competitive programmers).The sponsor list is not final and will be updated.

We are also thankful to have Codeforces as our hosting partner.

Who can participate?

Teams of 3 ready to rock and roll! No programming language, affiliation or problem solving methods restrictions. You only need to be at least 18 years old and have a slightly concerning enthusiasm for coding challenges.

Save the Date

April 12, 2025: Online Qualification (5 hours) – here at Codeforces

June 7–8, 2025: Onsite Final (24 hours) – Belgrade, Serbia

Problem setters and jury: Aksenov239, isaf27, NALP, Taube, Gassa, cdkrot, PavelKunyavskiy, tourist, qwerty787788, MaxBuzz, pvs, Solenoid555, nsychev, naagi

Registration opens soon – you have enough time to find a team. Leave your email here and you will be the first to register.

See you at Midnight!

The European Championship 2025 will take place on the 2nd of March in Porto. The top teams from the European ICPC regionals CERC, NWERC, SEERC, SWERC will compete for the title of European champions. It is the second edition of this ICPC super-regional.

The mirror contest European Championship 2025 - Online Mirror (Unrated, ICPC Rules, Teams Preferred) will be held on Codeforces at Mar/02/2025 13:35 (Moscow time) and will last 5 hours.

The mirror contest will feature the same problems as the official competition, except for one problem, which will be presented in a more challenging version.

I am the chief judge for the competition and I want to thank:

• The amazing set of judges who proposed and prepared the problems: bicsi, cip999, cdkrot, Egor, gangsterveggies, Giove, Jorke, Petr, thocevar.
• Our beloved tester ksun48.
• Everyone involved in the organization of EUC, in particular our director Fernando Silva.
• The developers of DOMjudge, the contest system used in the official contest.
• MikeMirzayanov for Polygon (that we used to prepare the problems) and for letting us host the mirror on Codeforces.

I invite you to participate in the contest and I hope that you will like the problems.

On the difficulty
The contest features problems with difficulties from div1A to div1E. It should be enjoyable for many, and interesting even for the strongest teams in the world.

Rules

1. The contest is unrated, so your codeforces rating will not be affected.
2. The scoring is ICPC-style: teams are first sorted by number of problems solved, then the time-penalty is used as a tie-break. An incorrect submission gives a 20 minutes penalty.
3. We encourage participation as a team.
4. If you are participating in a team, we encourage you to use only one computer for coding the solutions (as in an ICPC contest). Regarding using templates, googling, and copy-pasting code: feel free to do it.

UPDATE 1: Here you can find the editorial: https://codeforces.me/blog/entry/140239

UPDATE 2:

Congratulations to the winners, and especially to the first team for AK:

1. [?]: LeoPro, fastmath, turmax
2. jiangly
3. [HoMaMaOvO] hos.lyric, maspy, maroonrk

Hi,

We would like to invite you to participate in the live online mirror contest of The 2025 ICPC Asia Pacific Championship next weekend. ICPC Asia Pacific Championship is the contest for top non-winning teams from all regional contests in the region to qualify to the World Finals. See the region rules and competition page for more details.

The official contest is scheduled to start at Saturday, 1 March 2025, 10am (UTC+8). The live online mirror contest is scheduled to start only 5 minutes later, to keep both contests run almost in sync. The contest is 5 hours long and consists of several problems.

Please note that we might have to postpone the live online mirror contest in case the official contest is delayed. This is to the ensure that the tasks are not available to the public until the official contest starts.

The contest will use ICPC-style scoring (same as the official contest) and will be unrated. You can participate as an individual or as a team, although as a team of three members is preferred.

See you on top of the leaderboard.

The 2025 ICPC Asia Pacific Championship Judges

[UPD]: Task analysis: https://apac.icpc.global/assets/competition/problem-analysis.pdf

مرحبا, Codeforces!

Translation: Hello, Codeforces!

We are super excited to invite you to participate in Codeforces Round 1007 (Div. 2), which will be held on Friday, February 28, 2025 at 17:35.

This round will be rated for all participants with rating below $$$2100$$$. Participants with higher ratings are encouraged to participate out of the competition.

You will be presented with $$$6$$$ or $$$7$$$ problems and $$$2$$$ hours and $$$15$$$ minutes to solve them. The problems are authored and prepared by Al-Merreikh, ApraCadabra, FzArK, limbo16, MOUFLESS, and Vectors_Master.

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

• Sugar_fan for coordinating the round and helping with problem preparation.
• satyam343 for improving some problems and providing suggestions to help us make the round better.
• Our army of testers: StarSilk, fallleaves01, _istil, rui_er, N_z__, Error_Yuan, Kaitokid, Proof_by_QED, Boboge, The_Hallak, Wael_Zaiback, Igor_Parfenov, Mohanad_Nahhal, hocln, ammar2000, ALAov, too_rusty, BabaVoss, MaherSefo, satyam343, larush, purp4ever, ZaiBug, The_Starry_Night, ginger.swap02, Shawerma, and spaghetti_coder for testing our round and providing invaluable feedback.
• MikeMirzayanov for the amazing Codeforces and Polygon platforms.
• Alexdat2000 for translating the statements into russian.

• You

  for participating in this round.

The score distribution will be as follows:

We hope you will find a non-empty subset of problems to be interesting. Good luck, have fun and see you in the standings on Friday!

Let's continue the series of announcements with a photo of the authors. We only managed to find one photo with three of us, another with two, and one with just a single person. Enjoy figuring out who’s who!

UPD: Congratulations to the winners!

All participants:

1. ksun48
2. maspy
3. potato167
4. jiangly
5. RGB_ICPC4

Rated only:

1. RGB_ICPC4
2. SuRiNonSul
3. lequoctran181
4. LifeWillChange
5. tuamitk42

UPD: Editorial has been posted. Check it out!

Hello Codeforces!

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

On Feb/27/2025 17:35 (Moscow time) Educational Codeforces Round 175 (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.

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

Good luck to all the participants!

Our friends at Neapolis University Pafos also have a message for you:

Admission to the Computer Science and Artificial Intelligence bachelor's program at Neapolis University Pafos is open!

The JetBrains Foundation supports this bachelor's program and offers 15 fully funded scholarships for the most talented applicants. The scholarships cover tuition, accommodation, medical insurance, visa fees, and pocket money (€300 per month).

First admission round:

• Application deadline – April 23, 2025
• Entrance test – April 27, 2025

UPD: Editorial is out

Hi everyone!

ne_justlm, itz_pabloo and I would like to see you as participants of Codeforces Round 1006 (Div. 3), which starts at Feb/25/2025 17:35 (Moscow time).

The round will be held according to the rules of educational rounds. Thus, during the round, tasks will be tested on preliminary tests, and after the round there will be a 12-hour open hacking phase (we really hope that not too many solutions will fall during it).

How the next announcement is made:

• this is where copy-paste starts,

here is your text, icpc rules, etc.

• this is where copy-paste ends.

You will have 2 hours and 15 minutes to solve 7 problems. The penalty for an incorrect submission will be 10 minutes.

We remind you, that only reliable participants of the third division will be included in the official results table. As it is written on the link — this is a necessary measure to combat unsportsmanlike behavior. To qualify as a "trusted" member of the third division, you must:

• take part in at least two rated rounds (and solve at least one problem in each of them),
• don't 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 (or you are a newcomer/unrated), you may choose to participate rated or unrated.

We would like to thank MikeMirzayanov for the Codeforces and Polygon platforms, and Vladosiya for incredibly cool coordination of round preparation.

As well thank you very much we would like to say to Kirill_Maglysh for his huge help in creating this round.

Also thanks for our testers:

• Ormlis, isaf27 for nutella testing.

• tch1cherin, WLZ for red testing.

• Egorsa, shadow9236, cry, alexsushin, Sokol080808 for honey testing.

• Dck, FBI, pskobx for the illusory technique — purple!

• Ianis, kaferius_cf, NerfThis, ukhalikshina, umezo, MiniBess, hump-and-bump, Kosya for such a familiar and close, water testing.

• tih-a, mkshh, Pozercpp, Kraska, radodododo, giorgi_pkhaladze and I hope the universe will be merciful to you.

• myav, sujan_roy24, t.muksunov, imtheonly1, DevUt for pleasant natural testing.

UPD: EDITORIAL ON CF Editorial

The best and brightest programmers from around the world have gathered this week in Dongguan, China, for the highly anticipated 2025 Universal Cup Finals!

Event Details

• Date: Saturday, February 22nd
• Start time: 10:30 AM CST (2:30 AM UTC)
• See participating teams
• Full schedule can be found here

Streaming

Witness the best contestants in the world as they push the boundaries of skill and strategy. You can be part of this event by following us online either on English Channel or Chinese Channel.

Mirror Contest

Join the mirror contest and compete in real-time with the finalists from anywhere in the world. Any Universal Cup registered team can participate. The mirror contest is available here, you may use your Universal Cup team account or register a new account to participate in the mirror contest.

Stay Tuned for the Conference

This isn't just a competition – it's a global celebration of competitive programming. Join us for The 2025 Universal Cup Conference for Competitive Programming on Sunday, February 23rd. Listen to insightful discussions with the brightest minds in the field.

The Conference will be streamed on jiangly's channel.