Hello everyone!

Some of you are using Codeforces to host private onsite contests. When doing so, you may want to give extra time to a participant due to technical reasons (maybe they had a problem with their PC so they lost some time from the contest).

Previously it was only possible to increase contest duration for everyone, but now you can do this selectively.

Navigate to the contest registrants page, and you will see all the contestants and will be able to add extra time there, given you are the contest manager.

We would like to know if there are any issues with this new feature, so let us know if you encounter any.

PS: Also, similarly to previously implemented feature for comments you can now change your vote on a blog post within a minute.

Namaste Codeforces!

We, CodeClub, the Computer Science and Engineering Department Club of IIT Kharagpur, are glad to invite you to participate in our landmark 25th CodeNite — Codeforces Round 1033 (Div. 1 + Div. 2) and CodeNite 2025, which will take place on Jun/21/2025 17:35 (Moscow time).

You will be given 8 problems and 2 hours 30 minutes to solve them. This round is a combined round and will be rated for everyone.

The problems are prepared by aryansanghi and the amazing former CodeClub President harshith_04. Special thanks to picramide for his support throughout the process and for his help in preparing the problems.

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

• SSerxhs for schzmooth coordination.
• Alexdat2000 for Russian translation.
• picramide, morphinecode, and anubhavdhar for providing some problems that couldn't make it to the round.
• Um_nik, turmax, ugly2333, le0n, jqdai0815, StarSilk, physics0523, fallleaves01, tiger2005, tarjen, IceKnight1093, Serval, Dominater069, satyam343, djm03178, huansir, sai-17, anubhavdhar, weirdflexbutok, Proelectro444, Little_Sheep_Yawn, Retired_shstyle, Theresa_Apocalypse, nanani, shorya1835, fr200110217102, chromate00, vivan_01, envariant, isosceles, pastimeplays, chrisrex, ssp2004, psp_09, .XiaoXia, Newtech66, Me_as_coder for testing and providing useful feedback.
• KAN for the initial review of the problems and overall coordination.
• MikeMirzayanov for the amazing Codeforces and Polygon platforms.

We really hope that you like the problems. Shubhakamana tatha vijaya!

UPD1 Score Distribution: $500-750-1250-1750-2500-3000-3500-4000$

Hello, Codeforces! 👋👋👋

Codeforces Round 1032 (Div. 3) will start at Jun/17/2025 17:35 (Moscow time). You will be offered 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 2 hours and 15 minutes to solve the problems.

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.

I would like to express my gratitude to:

• Vladosiya for the excellent coordination of the round.

• Sugar_fan for red round testing.

• cry, Friendiks, EzikBro, Ste for orange round testing.

• Egorov_Dmitriy, katzi, KotlechkovEgor for purple round testing.

• Chugunov_Alexander, itz_pabloo, IceHydra, NicoRobin, OutrunMyGun, gbula for blue round testing.

• _supersonic_, ne_justlm for the cyan round testing.

• MikeMirzayanov for Polygon and Codeforces systems.

Good luck! 🔥🔥🔥

Editorial!

Hello, Codeforces! We're glad to invite you to take part in Codeforces Round 1031 (Div. 2), which will start on Jun/15/2025 12:05 (Moscow time). Note the unusual start time of the round. You will be given 6 problems and 2 hours to solve them.

This round will be rated for participants whose rating is below 2100. Participants with higher rating can participate unofficially.

The problems were authored and prepared by bashkort, TheEvilBird, 127.0.0.1, Mangooste and Moscow Olympiad Scientific Committee.

The round is based on All-Russian olympiad in the name of Keldysh.

We would like to thank

• Artyom123 for his high-speed coordination;
• A_G, ahsoltan, Proof_by_QED, larush, Mikhango, Ormlis, _istil for testing;
• MikeMirzayanov for creating Codeforces and Polygon.

Good luck everybody!

UPD: Score distribution: $500 - 750 - 1250 - 1750 - 2500 - 3000$

UPD2: Editorial

This weekend concluded the first season of the Midnight Code Cup with a long-awaited 24-hour contest. 29 teams – the best from the qualification round, including the qualification winners Omogen Heap – competed on-site in Belgrade, Serbia, on June 7-8.

Team Omogen Heap jumped into first place around the midpoint of the contest and held the title until the very end. Congratulations to our first Midnight Code Cup champions on their dominant performance! Second place went to team GoodBye2023, and Jinotega finished in third.

Final results: https://2025.midnightcodecup.org/standings/
Problems: https://2025.midnightcodecup.org/problems/
Photos: https://drive.google.com/drive/folders/1i6Ap3OEz7hLNv2r5PAIQSwsINGpv9UxH?usp=drive_link
Instagram: https://www.instagram.com/midnightcodecup

Huge thanks to our jury: chief judge Aksenov239 and the team cdkrot, Gassa, isaf27, MaxBuzz, naagi, NALP, nsychev, PavelKunyavskiy, pvs, qwerty787788, Solenoid555, tourist, winger, George Marcus, Timofei Vasilevskii, Vadim Kharitonov. And our clutch testers: antonkov, Belonogov, enot110, izban, Psyho, subscriber, VArtem. Our generous sponsors and partners: Recraft, JetBrains, Jane Street, Neon, Pinely, Amazon and Nebius. And, of course, Codeforces, for hosting the qualification round.

Congratulations to the finalists! Please share your thoughts about the problems and the contest in the comments – and don’t forget to post the cutest solutions to problem I! Below is a write-up of the contest from the organizing team and judges.

Üdv, Codeforces!

Error-42, gortomi and I are glad to invite everyone to participate in Codeforces Round 1030 (Div. 2), which will be held on Jun/12/2025 17:35 (Moscow time). You will be given 6 problems and 1 subtask with 2 hours to solve them.

The round will be rated for participants of Division 2 with a rating lower than 2100. Division 1 participants can participate unofficially.

All problems are authored by Error-42, gortomi and me.

We would like to thank:

• satyam343 for their amazing coordination and for rejecting our bad ideas ${\color{white}{\text{and several other problems too.}}}$
• peti1234 for their LGM opinion.
• Alexdat2000 for the Russian translations.
• N_z__, Error_Yuan, _istil, busamate, andrei_boaca, Dominater069, nifeshe for ruby testing
• Proof_by_QED, zsombor, Valaki2, lacito, Peti, zsmihaly, de_sousa, 18o3, SeptaCube, efishel, cry for amber testing.
• sangeraf, harshith_04, Morisz10, monadtransformer, MasterRayuga, dkg7888, JagguBandar for amethyst testing.
• SpyrosAliv, Non-origination, chromate00, jampm, hashman, lordlorinc, Doraho, larush, dedsec_29 for sapphire testing.
• UVince for the only apatite testing.
• Albertstein for the only obsidian testing.
• MikeMirzayanov for the almighty Codeforces and Polygon platforms.

We hope you will enjoy and have fun in the contest. Sok szerencsét!

UPD1: Score distribution: 500 — 1000 — 1000 — (1250 — 1000) — 2500 — 3500

UPD2: Thanks for participating, editorial is out!

UPD3: Congratulations to the winners!

Div. 1:

1. tourist
2. ksun48
3. tiger2005
4. maspy
5. StarSilk

Div. 2:

1. geniorzity
2. GongKai
3. 2ky
4. Bronya_H
5. hondacity

أهلاً, Codeforces!

cry, Intellegent, and I are really excited to invite you to participate in Codeforces Round 1029 (Div. 3), which will take place on Jun/08/2025 17:35 (Moscow time). You will be given $2$ hours and $15$ minutes to solve $8$ problems.

The round will be hosted by rules of educational rounds (extended ICPC). Thus, all solutions will be judged on preliminary tests during the round, and after the round, there will be a 12-hour phase of open hacks. After the open hack phase, all accepted solutions will be rejudged on successful hacks. Also, note that there is no score distribution but the usual penalty of 10 minutes for each wrong submission, following the rules of educational rounds.

Note that the penalty for each wrong submission in this round is 10 minutes. Also, note the rule restricting AI use. If you are caught using AI in an unorthodox manner, you will be sent to cry's basement. You don't want that to happen.

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 rating of 1900 or higher at any moment in time.

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 (unless you register unrated).

I would like to thank the following people for making this round possible:

• cry for being an amazing coordinator and being even more amazing to add a problem to the set, and Intellegent for adding a wowee problem to the set.
• Dominater069 for red testing.
• Proof_by_QED, __baozii__, AksLolCoding, amoeba4, catgirl, efishel, -firefly-, Edeeva, 18o3 for orange testing.
• reirugan, LMeyling, wuhudsm, rewhile, IceWolf898 for purple testing.
• macaquedev, hashman, SpyrosAliv, chromate00, Non-origination, expertaq, DivinePunishment for blue testing.
• Borhom, _Rawan_, ETL for cyan testing.
• hotfog12 for grey testing.
• rlin61 for unrated testing.
• Vladosiya for statement translation and testing as well.
• MikeMirzayanov for developing Codeforces and Polygon.

Good luck, and most importantly, have fun!

EDIT: Tutorial

Hello Codeforces!

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

On Jun/03/2025 17:35 (Moscow time) Educational Codeforces Round 179 (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.

Almost all of the problems in the round were invented and prepared by me. I would like to thank Ivan BledDest Androsov for the problem that made the round more balanced.

And once again, I would like to express my sincere thanks to the round coordinators: Ivan BledDest Androsov and Mikhail awoo Piklyaev for improving the quality of the problems and helping with their preparation.

And of course, huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

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 ongoing!

The JetBrains Foundation is offering 20 fully funded scholarships for talented first-year students.

Each scholarship covers the entire duration of the program, including tuition, accommodation, medical insurance, visa fees, and €300 per month for personal expenses.

Good news! If you missed the first round, there’s still time to apply for the second round! Submit your documents, pass the entrance test and interview, and receive a full scholarship.

• Application deadline – June 11, 2025
• Entrance test – June 15, 2025 (this is the last entrance test for 2025!)

Additionally, there are 2 fully funded scholarships available for students wishing to transfer into the second year of the program (for those already studying Computer Science).

If you have any questions, feel free to ask in the Telegram chat or email us at nup@jetbrains.com !

UPD: Editorial is out

Hello, Codeforces!

I'm pleased to invite you to Codeforces Round 1028 (Div. 1) and Codeforces Round 1028 (Div. 2). It starts on May/31/2025 17:35 (Moscow time). This means that Children's Day will come during this round. I'm sure everyone will be impressed with Children's Day, even if they're no longer children.

I remember when I was a kid, I always looked forward to Children's Day. On Children's Day, there were always candies and fun activities at school. But as I grew up, this festive atmosphere was diluted by the trivialities of life. But luckily, we had Codeforces. Spending the holidays with interesting problems doesn't actually have to be more boring than candies and activities ¯\_(ツ)_/¯

This will be the second round I've hosted on Codeforces. To make it better, this time I've called on my friend MagicalFlower to help me organize this round. Also, errorgorn has helped us very much, we are fully indebted to this well known 🐸 on Codeforces!

For both divisions, you will have 2 hours to solve 6 problems. I hope you will enjoy these problems.

I would like to thank:

• errorgorn for his 🥵 and 🥶 coordination.
• Alexdat2000 for Russian translation.
• MagicalFlower for providing more rejected problems than me. While you may not be able to see these problems, these efforts cannot be ignored. 👈🤣
• jqdai0815 for existing and VIP Testing.
• JoesSR, qiuzx and 275307894a for Legendary Grandmaster Testing.
• zhaohaikun, N_z__, HealTheWorld, _istil, grass8sheep, EasonTAO and ffao for International Grandmaster Testing.
• Error_Yuan, H_W_Y, Hanghang007 and bribritt for Grandmaster Testing.
• tarche for International Master Testing.
• ODT, Tyx2019, Hank2019, Bazoka13 and bookcat for Master Testing.
• Shoryu386 and ToxicPie9 for Candidate Master Testing.
• daitangchen2008 for Specialist Testing.
• zhufangyi, ls114514, clare_288, Awd_, wengxuanyu, likerun and JessicaZhang for Newbie Testing.

• You for participating the round.

• MikeMirzayanov and KAN for Codeforces and Polygon systems.

Especially, I'd like to thank JoesSR, zhaohaikun and ToxicPie9 for helping us prepare this round, which might not be able to run as smoothly as now without them.

Finally, I would like to give my heartfelt thanks and praise to errorgorn.

Both of the rounds I hosted would not have been possible without the support and efforts of errorgorn. Although he often rejected my problems 💀 and stood me up a lot 😡, I could sense his love for the problems and his seriousness about the competition in the time we spent together preparing for these rounds.

errorgorn is an interesting guy, you can often see him sending funny emoji like 🤯 in the discord, and he would also sometimes share me with some of the local culture of Singapore. I am so lucky to have had this fun time with him.

Some time ago, errorgorn happened to tell me that he might not have time to continue as Coordinator, which I deeply regretted. Likewise, I'm starting my college career, and this will probably be the last round I host at Codeforces as well.

Hopefully this round will be a perfect end to my experience hosting rounds on Codeforces. It's really quite an unforgettable experience, and I'm also looking forward to the next collaboration with errorgorn.

The main character of the problems will be Gellyfish🍏, and her friend Flower🌸.

Score distribution:

• Div.1: $500-1250-1750-2250-3000-(2500-3500)$
• Div.2: $500-750-1250-2000-2500-3000$

Good Luck & Have Fun! 🔥🔥🔥

UPD1: Congratulations to the winners!

UPD2: Editorial is out.

Hello, Codeforces!

I have a short update. With the help of Kleidemos, we've improved C# support. You can now use the modern dotnet-9, and the C# language version has been upgraded to 13. Additionally, the F# language (version 9) is now supported as well. Both compilers are currently in experimental mode. Once we make sure everything works smoothly, I'll remove one of the older C# versions and leave only two.