Hello, Codeforces!

The TG channel team @KogutIvanTutoring is pleased to invite you to participate in Codeforces Round 1016 (Div. 3) on Apr/08/2025 17:35 (Moscow time) — another Codeforces round for the third division. This round will feature 7 problems selected in difficulty to create an interesting competition for participants with ratings up to 1600. However, anyone with a rating of 1600 or higher can register for the round out of competition.

The round will follow the rules of educational rounds. Thus, during the round, the problems will be tested on preliminary tests, and after the round, there will be a 12-hour phase of open hacking. After this phase, all successful attempts will be retested on successful hacks. We have tried to create decent tests — just like you, we will be disappointed if many solutions fail after the contest ends.

You will be offered 7 problems and 2 hours 15 minutes to solve them.

The penalty for an incorrect attempt in this round will be 10 minutes.

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

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

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

The problems were conceived and prepared by part of our team: fstilus, EzikBro, _icy_, Boodoochai, pskobx, gravitsapa

Also, a big thank you to:

• MikeMirzayanov for the Polygon and Codeforces systems.

• Vladosiya for coordinating the round.

• Madball, Merkurev for red testing of the round.

• a.stepanov281005, reshke, Pagode_Paiva, AC_sahER for orange testing of the round.

• Alexbrii for purple testing of the round.

• Friendiks, Wileyne, margothequeen, Tainel, darysani, Pistol_Engineer, CarlosS48 for blue testing of the round.

• im_sad_now, veliak, harpreet1237 for cyan testing of the round.

• NeNichiy, alice19, Telyatnikov_Mikhail for green testing of the round.

Good luck to everyone!

UPD. Editorial is out!

Greetings Codeforces!

First things first, we would like to thank everyone who participated in the previous eleven Kotlin Heroes competitions: Episode 1, Episode 2, Episode 3, Episode 4, Episode 5: ICPC Round, Episode 6, Episode 7, Episode 8, Episode 9, Episode 10 and Episode 11.

Kotlin Heroes is a great way to play around with Kotlin’s features, learn something new, and practice using the language by solving fun problems. It is great for programmers of any level!

We invite you to join the practice round, where you can improve your algorithmic problem-solving skills and complete training problems. In this round, all the solutions are open and you can request hints if you’re stuck.

Here are some things you can do to help you refresh your knowledge of Kotlin and learn more about competitive programming while you practice:

• Review our Kotlin solutions for the Advent of Code algorithmic puzzles.
• Read our competitive programming tutorial.
• Watch the videos from our Kotlin in Competitive Programming YouTube playlist.
• Look at the problems from the previous practice rounds.

On April 7, 2025, the real challenge begins! Kotlin Heroes: Episode 12 will last 2 hours 30 minutes and will feature a range of problems – from simple tasks anyone can solve to tricky challenges for seasoned competitive programmers.

The contest will contain at least one interactive problem, so we strongly recommend that you familiarize yourself with them — for example, by solving problem F from the practice round and/or reading the Codeforces guide for interactive problems. The flush operation in Kotlin is done by calling System.out.flush().

The use of AI-based tools during the main contest is strictly limited. To find out the guidelines for proper AI use, what is allowed and what is prohibited, please read the post "Rule Restricting the use of AI". Improper use of AI tools during the main contest may result in disqualification.

Prizes:

The top three winners will receive cash prizes of $512, $256, and $128 (or rewards of equivalent value), respectively. The top 50 participants will win a Kotlin Heroes T-shirt and an exclusive Kotlin sticker, and all competitors who solve at least one problem will be entered into a raffle for one of 50 Kotlin Heroes T-shirts.

Please note that we are not able to ship prizes to any country, state, province, or territory subject to comprehensive OFAC sanctions, including Belarus, Cuba, Iran, North Korea, Russia, Syria, or the Crimea, Donetsk, or Luhansk regions. For complete the list, please visit this page.

Best of luck to everyone!

UPD: You can find the editorial here. Thank you for participation!

Hi, Codeforces!

We are pleased to invite you to Teza Round 1 (Codeforces Round 1015, Div. 1 + Div. 2), which will be held on 05.04.2025 17:35 (Московское время)

The problems are authored and prepared by CharlieV and me. You will be given 8 problems, one of which is divided into two subtasks, and 3 hours to solve them. The round will be rated for everyone.

I would like to thank everyone who has helped prepare for this round:

• Sugar_fan for his excellent coordination.
• Alexdat2000 for the Russian translation.
• CharlieV, ExplodingKonjac, QwQwf, sinsop90 for providing problem ideas despite a few unused.
• 244mhq for reviewing some of the problems when coordinating my previous rounds.
• EvenImage, StarSilk, 244mhq, N_z__, yeminghan, Error_Yuan, dieselhuang, CutieSmileHaruka, QwQwf, Hanghang007, shstyle., gdf_yhm, 66E61d, beaten_by_ai, Yandere for testing the round and providing useful feedback.
• MikeMirzayanov for Codeforces and Polygon.

The score distribution is $$$750 - 1000 - 1500 - 1750 - 2250 - 3000 - (2500 - 1750) - 3750$$$.

Good luck, have fun!

And now, a few words from today's sponsor!

Greetings, Codeforces Talents!

We are thrilled to invite you to Teza’s first Codeforces competition!

Participants will have a chance to win Teza sticker packs and T-shirts:

• The top 25 ranked competitors.
• 25 randomly selected from places 26-100.

As a systematic quantitative hedge fund, we know that exceptional talent drives success—so seeing this community come together is truly exciting.

Good luck to all participants! And for those not competing, thank you for stopping by—if you're passionate about technical and algorithmic challenges, solving Olympiad-style problems, and diving into data-driven research, we’d love to connect.

Check out our career opportunities here and explore where your skills can take you. To join our team, please fill out the form.

Enjoy the competition and happy coding!

UPD 1: Score distribution changed.

UPD 2: Editorial is released.

UPD 3: Congratulations to the winners!

1. zhoukangyang (Congratulations on solving all problems!)
2. Ormlis
3. ecnerwala
4. Benq
5. maroonrk
6. LJC00118
7. Kevin114514
8. tourist
9. 0tesmem
10. jiangly

Hello Codeforces!

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

On Apr/03/2025 17:35 (Moscow time) Educational Codeforces Round 177 (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 problems and 2 hours to solve them.

The round is based on the problems from the Open Championship of Karelia in competitive programming.

The problems were invented and prepared by Galina Galina_Basalova Basalova, Valentin Valentin_E Ermishin, Lev robotolev Provotorin and me.

I would like to thank the authors of the championship problems whose tasks were not included in the final set for the round: Ruslan r314 Alkin, Yuriy basalov_yurij Basalov, Alexey ashmelev Shmelev, and Nikolay Nicola95 Ermolin.

I would also 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.

Big thanks to our testers: Brovko, deni1000, KIRIJIJI, shnirelman, Alenochka, slash0t, LightSky, infinite_meltdown, Knh_era, M1chail, Antithesis, Kolychestiy, neohacker for their valuable advice and suggestions!

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 open!

The JetBrains Foundation supports this bachelor's program and offers 20 fully funded scholarships for talented first-year students. They initially announced 15 scholarships but have now increased the number to 20 to give more students the opportunity to join the program.

Each scholarship covers entire duration of the program, including tuition, accomodation, medical insurance, visa fees, and €300/month pocket money.

They are also offering now 2 fully funded scholarships for students transferring into the second year of the program.

First admission round:

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

UPD: Editorial is out

Hello, Codefoolers!

We, AlperenT, flamestorm, prvocislo, temporary1, ToxicPie9, and -1e11, would like to invite everyone on Codeforces to April Fools Day Contest 2025! The 13th April Fools Day Contest will take place on 01.04.2025 17:35 (Московское время). 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 $$$\sum\limits_{x=1}^{\infty} \frac{1}{x^n}$$$ converges 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, 2024

Thanks to our precious testers (they exist, trust me):

Please do not bother sending clarification requests in the contest as we obviously do not enjoy sending funny responses like we did in the last two years. It is definitely not the most fun part of April Fools.

Lastly, we have a video editorial this year (Russian captions available)!

Good luck, and have fun!

Edit 1: Editorial is out!

Edit 2:

Congratulations to the winners:

1. ksun48
2. Madball
3. iakovlev.zakhar
4. tiger2005
5. errorgorn

And the first solves on each problem:

• A: vladimirfilip
• B: Auchenai01
• C: Dark (after AprilFoolsClairvoyant)
• D: koishi.komeiji
• E: jiangly
• F: tiom4eg
• G: BucketPotato
• H: N/A (but circle977 got closest with every word except 10th)
• I: SeptaCube
• J: fishy15 (initially conqueror_of_tourist, but got hacked after the contest)

Photo of the authors back in 2019

Xin Chào, Codeforces! (☆^ー^☆)

We are thrilled to invite you to participate in Codeforces Round 1014 (Div. 2), which will be held on Mar/29/2025 17:35 (Moscow time).

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 offered 6 problems and 2 hours to solve them. The tasks were authored and written by k1sara and sergeev.PRO. We hope you enjoy the challenge!

A heartfelt thank you to everyone who made this round a reality:

• 244mhq and Um_nik for expertly coordinating the contest and offering invaluable guidance throughout the process,

• makrav, zltzlt, IzhitskiyTimofey, sadness, Noinoiio, max0000561, Vash_nick, yunetive29, ItsNotMeItsYou, DimonKrutoi, dope, Fu2o, Mikhango, re-wa-tl-ok, VictorKleymenov for testing our round and providing impactful feedback,

• danya111 for coming up with some exceptionally riveting excuses as to why he’s too busy to test our round,

• sergeev.PRO for being an amazing co-author, for putting up with my endless complaints, and for generously letting me copy every math homework over the past five years,

• MikeMirzayanov for the fantastic Codeforces and Polygon platforms.

• You for participating in the round.

[UPD 1] The score distribution (now changed) will be as follows:

[UPD 2] EDITORIAL

[UPD 3] Congratulations to the winners!

All participants:

1. ksun48
2. potato167
3. arvindf232
4. conqueror_of_tourist
5. maspy

Rated only:

1. namcartoon06
2. Milashka
3. chanshin9211
4. IuNgocBich
5. abhaydixit500

Greetings, Codeforces Talents!

We are thrilled to invite you to Teza’s first Codeforces competition!

Teza, founded in 2009 as a high-frequency trading firm, has evolved into a leading systematic quantitative hedge fund. From equities to options, futures, and crypto, we transform complex mathematical concepts into financial strategies that operate across the world's largest markets.

Our team is composed of some of the brightest minds in the industry, including International Olympiad winners in Physics and Mathematics, and the youngest individuals ever to earn double Ph.D.s in Computer Science and Physics from MIT. Our CEO, Misha Malyshev, a MIPT graduate with a Ph.D. from Princeton, is known for setting an unbeaten world record for returns on capital on Wall Street. Learn more about Misha.

We have a team member who has discovered a new star, highlighting our commitment to pioneering exploration in all fields. We believe that only exceptional minds make markets efficient.

Good luck to all participants! And for those not competing, thank you for stopping by — if you're passionate about technical and algorithmic challenges, solving Olympiad-style problems as your day-to-day job, we’d love to connect.

Check out our career opportunities here and explore where your skills can take you.

Enjoy the competition and happy coding!

Hello, Codeforces \[^-^]/

The competitive programming laboratory of the IT campus NEIMARK from Nizhny Novgorod is pleased to invite everyone to participate in Codeforces Round 1013 (Div. 3), which will be held on Mar/25/2025 17:35 (Moscow time).

The round is based on the problems of the final of the first olympiad by IT campus NEIMARK. 312 students from 28 subjects of the Russian Federation took part in the olympiad. And at the final competition, in addition to Nizhny Novgorod students, we met finalists from the Chuvash Republic, Moscow, Tolyatti, Kirov, Saransk and Ulyanovsk.

If you participated in the final of this olympiad, please refuse to officially participate in this round.

The topics of the tasks will be related to the working days and weekends of our laboratory. The laboratory has existed for a little less than a year, but during this time several training camps, many personal and team trainings have been held, and dozens of tasks for school and student competitions have been developed (you can find some of these competitions in the section Gym). We opened competitive programming clubs in schools in Nizhny Novgorod, and began training interested IT teachers. We also acted as a venue for several programming competitions.

And at Mar/25/2025 17:35 (Moscow time) we will finally share with you one of the most important results of our work.

You will be given 7 problems and 2 hours and 15 minutes to solve them.

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

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.

Remind yourself 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).
• 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).

We hope you will enjoy problems! The tasks were prepared by our laboratory staff: Alexey ashmelev Shmelev, Islam l-_-l Shayakhmetov and Diana Diall_ Alyaseva.

Thanks to MikeMirzayanov for the CodeForces and Polygon systems. Thanks to Vladosiya for the coordination and help in preparing the round.

Thanks to our testers: MForest, OG_Matveychick1, Tmitmi, Riladavin, quaha, eepsilon, anotherworld, konred, NerfThis, gtheoden42, sasha00123, ReshuVse, artem., OG_Sergzhick2, bugrova, Itsmylove1

Good luck for everyone and praise the sun \[^-^]/

Upd. Editorial