Hello, Codefoolers!

We, AlperenT, Ari, ToxicPie9, flamestorm, prvocislo, temporary1, and willy108 would like to invite everyone on Codeforces to April Fools Day Contest 2026! The 14th April Fools Day Contest will take place on Apr/01/2026 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 $$$n$$$ problems where $$$n$$$ is the number of different AI models I used today 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.

There will be at least one non-interactive problem. In case you do not care about those problems, here is the guide for interactive problems.

Please note that the round is unrated and that the penalty for a wrong submission is 10 minutes. Furthermore, similar to other contests, it is not allowed to use AI help unless permitted in this blog.

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, 2024, 2025. 2026. (Does anyone ever click these anyway, why do I have to keep adding them each year?)

Thanks to our precious testers:

ChatGPT, Gemini, Claude, Grok, DeepSeek, and a few others who preferred to remain anonymous.

It is, without a doubt, the least enjoyable part of April Fools for us to respond to clarification requests with funny responses. It is certainly not the main motivator for us to prepare these contests in the first place. Therefore, please refrain from continuing this tradition.

Good luck, and have fun!

Hello Codeforces!

We are really excited to invite you to participate in Codeforces Round 1089 (Div. 2), which will be held on Mar/29/2026 17:35 (Moscow time).

You will be given $$$6$$$ "simple" problems and $$$2$$$ hour $$$15$$$ minutes to solve them. Note that one of the problems will be further divided into $$$2$$$ subtasks. Furthermore, some of the problems may be interactive, so please read the guide for interactive problems if you are not familiar with them. This round will be rated for the participants with rating lower than 2100.

The scoring distribution is as follows:

The problems are authored and prepared by simplelife, ritam1234, __baozii__, and me.

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

• cry for his orz coordination and support throughout the round, and also for rejecting a lot of problems.
• Alexdat2000 for Russian translation.
• __baozii__, wuhudsm and Intellegent for VVIP testing.
• VladiG, sammyuri and macaquedev for their "Special Contribution".
• Dominater069 for LGM testing
• kevinxiehk, awesomeguy856, sammyuri, _istil for Red testing.
• amsraman, awang11, Proof_by_QED, temporary1, VladiG, CutSandstone, -firefly-, AksLolCoding, Friedrich and 0x3F for Orange testing.
• SpyrosAliv, AkShukla, tin.le2, wakanda-forever and Edeeva for Purple testing.
• IceSerpent, DivinePunishment, chromate00, Ermiooo159, expertaq, Ananya_agr, alex_rider123, kryoton_98, susvent, Jteh, apollo07 and beaten_by_ai for Blue testing.
• nik_exists, dipamsen, GlidingNinja_ccn and RJ_Parin_fr for Cyan testing.
• ukcsstudent for Green testing.
• MikeMirzayanov and KAN for the Codeforces and Polygon platforms.
• And finally, You, for participating.

UPD : Editorial link. Hope you enjoyed the round. We are sorry for the unexpectedly hard C2.

UDP2 : Congratulations to the winners!

Top $$$5$$$ overall: (subject to change)

1. Geothermal
2. YuukiS
3. NotNanYan
4. yanchengzhi
5. im_xRayVN

Top $$$5$$$ rated participants: (subject to change)

1. NotNanYan
2. yanchengzhi
3. im_xRayVN
4. NekoType_
5. makeit427

Hello Codeforces

After countless nights of yapping, bedfight duels, and failed zero cycles

The authors of the three best Div. 1 of all time, nifeshe, chromate00, and I, have joined forces to create the Division $$$1+2$$$ round that will break the internet: Nebius Round 2 (Codeforces Round 1088, Div. 1 + Div. 2), which will be held on Mar/28/2026 17:45 (Moscow time). This round will be combined for Division $$$1$$$ and Division $$$2$$$ and will be rated for everyone.

You will have $$$2.5$$$ hours to solve $$$8$$$ problems. Between $$$6$$$ and $$$7$$$ problems will not be split into subtasks. Also, between $$$6$$$ and $$$7$$$ problems will not be interactive, so you are recommended to read the guide to interactive problems if you have not encountered them before.

We would like to thank the following people for making the contest possible:

• Um_nik for pre-reviewing the round.
• cadmiumky for the coordination and helping with preparation.
• BurnedChicken for VIP testing.
• Dominater069, Geothermal, EvenImage, and SomethingNew for LGM testing.
• sammyuri, __baozii__, dinohaur, Dragos, rolandpetrean, Sana, and _istil, for red testing.
• Lilypad, JeffreyLC, misteg168, AksLolCoding, mwen, and PMiguelez for orange testing.
• efishel, tvladm, and madlogic for purple testing.
• mathtsai, Jamshed11, lev1106, Argentum47, simplelife, and SpyrosAliv for blue testing.
• nik_exists for cyan testing.
• Alexdat2000 for translating statements to Russian.
• MikeMirzayanov for Codeforces and Polygon.
• and last but not least, You for participating!

The scoring distribution is below.

Now, a few words from our sponsor Nebius!

We are a Nasdaq-listed company building cloud infrastructure and hyperscale platforms for AI innovators worldwide. We support the entire AI lifecycle from training to deployment, powered by high-performance NVIDIA GPUs. Behind the platform is a global team of over 1400 people, including more than 400 engineers working at the frontier of AI, supported by a dedicated in-house AI R&D team.

We’re thrilled to invite you to enroll into our first Early Talent Program! It’s designed for students and new grads to learn, contribute to building AI infrastructure, and grow into core members of our team.

If you are interested, please fill in this form. It could be your opportunity to start your career journey at Nebius.

And last but not least about the prizes for Nebius Round 2.

We’ve got something exciting lined up for the top 15 contestants on the leaderboard. Rewards come in the form of credits for Nebius Token Factory – they can be spent on inferring AI models, eg. generating text or powering AI-driven applications or agents.

• 🥇 1st place – equivalent of $1000
• 🥈 2nd & 🥉 3rd places — $500 each
• 🥇 4th–15th places — $100 each

We hope you will participate and enjoy the problems. Good luck!

UPD: the contest has been delayed by 10 minutes to allow everyone to register.

UPD2: https://codeforces.com/blog/entry/152448 editorial

Hello, Codeforces! 👋

We’re Nebius.

You might remember our Welcome Round a few years ago, and we're back with another round! We invite you to take part in our Second round on Codeforces: Nebius Round 2 (Codeforces Round 1088, Div. 1 + Div. 2). Join us on Mar/28/2026 17:35 (Moscow time) and test your skills by solving problems!

In the meantime, we want to share something big.

We’re launching our first Early Talent Program for students and recent grads.

Quick intro. I used to coordinate Codeforces rounds back in 2014–2015, did IOI/ICPC, and was pretty active here in the 2010s. Now I’m a Director of Engineering at Nebius, working on our new agentic search direction. As a former intern of similar program, I’d be really happy to see more CF folks join us.

This is not a “watch and learn” internship. You’ll be working on real systems such as AI infrastructure, cloud, product, and AI RnD, shipping things, and having actual ownership.

What you get

Details

Roles and locations:

• AI Researcher — Amsterdam (HQ), Berlin, Remote (from Europe & United States)
• Backend Developer — Amsterdam (HQ)
• Full Stack Developer — Amsterdam (HQ)
• ML Engineer — Life Sciences — Amsterdam (HQ)
• AI/ML Specialist Solution Architect — Remote (from United States)
• Network Engineer — Amsterdam (HQ)
• Site Reliability Engineer — Amsterdam (HQ)
• Cloud Engineer — Amsterdam (HQ)
• Data Center Technician — Finland, United States, Paris, Tel Aviv

Who we’re looking for

• Students / recent grads / early specialists
• Strong fundamentals + interest in large-scale systems
• Candidates eligible to work full-time on-site in the role’s location

Use the link below to complete the application form for the open positions.

Till soon!

Hello, Codeforces!

__baozii__ and I are glad to invite you to participate in Codeforces Round 1087 (Div. 2). The round will take place at Mar/21/2026 17:35 (Moscow time). There will be $$$6$$$ problems, and you will have $$$2$$$ hours to solve them. The round will be held according to the Codeforces rules and will be rated for division $$$2$$$.

At least one problem will be interactive, so we highly recommend you to read guide for interactive problems before the contest.

UPD: score distribution:$$$500 - 750 - 1500 - 1750 - 2250 - 3000$$$.
UPD:editorial

We would like to thank:

• Sugar_fan for coordination.
• Alexdat2000 for Russian translation.
• MikeMirzayanov and KAN for the best platform.
• Um_nik, Dominater069 for nutella testing.
• Tobo, Intellegent, A_G, k1r1t0, _istil, nifeshe for red testing.
• 0x3F, Proof_by_QED, FelixArg, DNR, -firefly-, Timosh, Arpa for orange testing.
• madlogic, Amao_Fox, Jamshed11 for purple testing.
• chromate00, simplelife, Argentum47, satyam343, SkyWave2022 for blue testing.

Wishing everyone good luck and high ratings!

upd:

top $$$10$$$:

1. bismispis
2. 415411
3. TripleM5da
4. StarSilk
5. undefined_Ryan
6. maspy
7. Cody473
8. antontrygubO_o
9. YuukiS
10. potato167

top $$$10$$$ rated:

1. bismispis
2. undefined_Ryan
3. Cody473
4. qwertyuiojhygtfdfg
5. AJ123496
6. pixelcoder20
7. Ravnik
8. Khai2007
9. ixumqwq
10. _annhien_ruby22

Notes that there will be an update about the top $$$10$$$ after roll-back.

TL;DR: Register for the qualification round at https://midnightcodecup.com

Last year we decided to revive the craziest problem solving format of all — the 24-hour onsite. It turned out amazing, so we are bringing more craziness and problems this year.

We’re supported by incredible sponsors: Recraft, OpenAI, Nebius, Alber Blanc, Revolut, Logical Intelligence, and Pinely. Huge thanks to the teams at these companies for backing problem-solving minds – this is the way.

Join the qualification round here at Codeforces on April 11th at 1 PM UTC.

The best 25 teams + 5 wildcards will travel to Belgrade on July 4–5 for a 24-hour final. We can’t wait to see who makes it this year — and the jury will not be shy about challenging you.

Btw, please give it up for The Jury: Aksenov239, qwerty787788, cdkrot, tourist, nsychev, naagi, Gassa, Arpa, pashka, yulik.daniel, xiaowuc1, isaf27, mnaeraxr , aropan, Solenoid555.

Now go register, follow our newly created X account for updates and..

See you at Midnight!

Hello Codeforces!

The series of Educational Rounds continues thanks to the support of the Computer Science and Artificial Intelligence (CSAI) program at Neapolis University Pafos, with scholarships provided by JetBrains.

Educational Codeforces Round 188 (Rated for Div. 2) will start on Mar/16/2026 17:35 (Moscow time).

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 6-7 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, Alex fcspartakm Frolov and me. Also, 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:

CSAI: First admission deadline approaches — April 28, 2026.

Apply for the BSc in Computer Science & Artificial Intelligence at the Neapolis University Pafos. Up to 40 full scholarships, provided by the JetBrains Foundation, are available this year.

Key Dates

• Application Deadline: April 28, 2026, 11:59 pm UTC
• Mandatory Entrance Test: May 3, 2026

A great opportunity: ACTS 2026.2 Camp

To improve skills and prepare for intense programs like CSAI, we encourage applying for the ACTS 2026.2 Camp in Germany (July 10-20, 2026).

• Tracks: Competitive Programming and Software Engineering.
• Registration Deadline: April 18th.

Ready to advance your coding journey? Join a leading computer science community today! Apply now and visit our dedicated pages for more details on how you can get involved.

UPD: Editorial is out

Hello, Codeforces!

abc864197532 and I are pleased to invite you to Codeforces Round 1086 (Div. 2) on Mar/14/2026 17:35 (Moscow time)!

You will be given $$$5$$$ problems to solve in $$$2$$$ hours. Some of these problems are divided into subtasks. The scoring distribution is $$$500-1000-1250-(1250+1250)-3000$$$.

The problems of this round were prepared by tybbs, Mini_PEKKA and me. We would like to thank the following people for making this round possible.

• abc864197532 for his wonderful coordination.
• Alexdat2000 for Russian translation.
• __baozii__, _istil, ETO_leader, Fysty, WiwiHo, amano_hina, baluteshih and max0810 for red testing.
• Friedrich, Halberd_Cease and guagua0407 for orange testing.
• CSQ31, Maskrio, Murinho, Neil_Qian and raresh30 for purple testing.
• daniel071292, lev1106 and the_dragon_emperor for blue testing.
• afoasdfashdoif for black testing.
• MikeMirzayanov and KAN for the brilliant Codeforces and Polygon platform.
• You, for participating.

Good luck & Have fun!

UPD: The editorial has been published. Congratulations to the winners!

Div .1 and Div. 2:

1. ksun48
2. Nachia
3. A_G
4. YuukiS
5. ttamx
6. BurnedChicken
7. StarSilk
8. 244mhq
9. kotatsugame
10. 415411

Div. 2 Only:

1. debangsu_
2. masy2011
3. vlp
4. Conqueror5
5. lzh999
6. alex.krivoschecov
7. vld.ktk
8. ExtraNumber
9. XorGhost
10. 11Gaurav1

Hello Codeforces!

Kotlin Heroes: Episode 14 has wrapped up, and what an exciting round it was! Thanks to everyone who joined the contest, solved problems, and made this round another great Kotlin Heroes event.

We’ve already had many amazing rounds of the Kotlin Heroes series, and it’s incredible to see the community grow with each episode. Once again, we are proud to celebrate the true heroes of Kotlin who rose to the top and earned well-deserved prizes.

Top 3 contestants are:

1. Golovanov399
2. BucketPotato
3. literalchild

Kotlin Heroes T-shirts will go to the top 50 contestants:

These participants, who solved at least one problem, were randomly selected to receive special Kotlin Heroes T-shirts:

We’ll be in touch soon to coordinate prize delivery. Some participants from the previous round are still waiting for their Kotlin Heroes T-shirts due to shipping delays. We are working to resolve this and will make sure everyone receives their prizes. Thank you so much for your patience!

It's great to see new people learning Kotlin and performing brilliantly in the competition. Want to keep practicing? Challenges from all 14 previous rounds are available here: Episode 1, Episode 2, Episode 3, Episode 4, Episode 5: ICPC Round, Episode 6, Episode 7, Episode 8, Episode 9, Episode 10, Episode 11, Episode 12, Episode 13 and Episode 14.

If you’d like to sharpen your Kotlin skills, start with:

• Tour of Kotlin to learn the basics
• Algorithmic Challenges in Kotlin course, created by some of the competitive programming champions
• Competitive programming tutorial
• Videos on competitive programming in Kotlin from top competitive programmers

Stay tuned for future rounds, and we hope to see you again in the next Kotlin Heroes contest!

Hello, Codeforces!

IceSerpent and I are pleased to invite you to Codeforces Round 1085 (Div. 1 + Div. 2) on Mar/08/2026 17:35 (Moscow time)! While some of us will be turning our clocks an hour forward for daylight savings, our theme will turn it way back to the 2010s.

You will be given $$$8$$$ problems to solve in $$$3$$$ hours. Note that some of these problems are further divided into subtasks. Some of the problems may be interactive, so please read the guide for interactive problems if you are not familiar with them. The scoring distribution is as follows:

$$$\ \ \ \,$$$ $$$\ $$$ $$$\ \,$$$ $$$\,$$$ $$$\quad\ \ \ \ \,$$$ $$$\quad\ \ \ \ \ \,$$$ $$$\ \ $$$ $$$\qquad\ \ \ \ \ \ \ \,$$$ $$$\qquad\quad\ \ \ \ \ \ \ \ $$$

The problems of this round were authored by IceSerpent and myself, awang11. In addition, we would like to thank:

• 244mhq for his excellent coordination of the round and translating the problems to Russian;

• Um_nik for pre-reviewing the round;

• flummoxedfeline for providing beautiful illustrations;

• our army of testers, for their invaluable feedback and eagerness to testsolve: Um_nik, shcal, awesomeguy856, Extile, Noobish_Monk, __baozii__, Amazed, SomethingNew, awoo, -firefly-, ink31930, nik_exists, chromate00, cduckling, madlogic, Hori, misteg168, Dominater069, errorgorn, defnotmee;

• and of course MikeMirzayanov and KAN for the Codeforces and Polygon platforms.

UPD 1: The scoring distribution has been released!

UPD 2: Editorial is released at https://codeforces.com/blog/entry/151886. Hope you enjoyed the round!

UPD 3: The results!

Div. 1 + 2

1. ecnerwala

2. ksun48

3. tourist

4. turmax

5. hitonanode

6. jiangly

7. Elysion

8. Kapt

9. tickcross.y

10. StarSilk

First clears

A. LeonVir, 00:01

B. ksun48, 00:09

C. Golovanov399, 00:11

D. PelicanPilot, 00:16

E1. liaoyanxu, 00:14

E2. Ayush79, 00:33

F. littleju, 00:34

G. ainta, 01:25

H1 + H2 + H3. ecnerwala, 02:31