Hello, Codeforces!

The TG channel team @KogutIvanTutoring is pleased to invite you to participate in Codeforces Round 1043 (Div. 3) on Aug/21/2025 17:35 (Moscow time) — another Codeforces round for the third division. This round will feature 6-8 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 6-8 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, KotlechkovEgor, Wileyne, Friendiks, Boodoochai, pskobx

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, AC_sahER, Proof_by_QED, cry, fangcy for orange testing of the round.

• _IVON_, Gmacem, MiniBess, macaquedev, ego_death for purple testing of the round.

• EnigmaEon, margothequeen, semwin2008, Yassia, Pistol_Engineer, EduardoBrito, radodododo, Onomui for blue testing of the round.

• Art10em, MrYhatoh, dragoonSlayer for cyan testing of the round.

• NeNichiy, Rasel for green testing of the round.

• mlovbnee for gray testing of the round.

Good luck to everyone!

👋 Salam, Codeforces!

We are excited to announce that the final round of Rayan Programming Contest is set for November 25–29, 2025, in Tehran!

All participants ranked 1-1000 in the Rayan Selection Round are invited to complete the registration form by August 26, 2025. The final list of invited participants—selected based on rank and geographical diversity—will be announced shortly thereafter.

Beyond the chance to win top-tier prizes worth $40,000 USD, finalists will enjoy a unique opportunity to experience the timeless beauty and rich heritage of ancient Persia, with special highlights from the vibrant city of Tehran.

Hotel accommodation, local transportation, and meals are provided to all finalists. Moreover, a partial travel fund of 200 USD will be provided to all foreign participants (except prize winners).

🏆 World Finals 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

Furthermore, T-shirts for the top 50 participants of selection round as well as 50 more for randomly chosen participants ranked 51-1000 will be sent to those who complete the form. 👕

We look forward to seeing you on-site! 🎉

Hello everyone, we are happy to announce The 3rd Universal Cup Semifinals!

The Semifinals will be held online to determine the teams advancing to The 3rd Universal Cup Finals. The contest takes place on August 24, 2025, at 11:00 UTC (time in your local timezone) and will last 5 hours in the classical ICPC format.

The contest is open to everyone. If you haven’t registered yet, join us today!

For more information, please refer to our earlier announcements:

• Contest Rules Please read the rules carefully if you want to be a finalist! We have a proctoring rule this year!
• TechNotes
• Finals Qualification
• Live Stream

We sincerely thank the support from our event sponsors — Huawei and ZhenFund!

Looking forward to seeing you at the Semifinals!

Hello everyone!

Today we announce that Codeforces now supports OpenID Connect — authentication protocol based on the OAuth 2.0. This allows third-party websites to implement logging in with Codeforces.

If you want to implement this for yourself, create an OAuth app in API settings.

Codeforces includes user's handle, current rating and avatar url as part of the id token.

Let us know if you hit any issues!

Hello Codeforces!

We are glad to invite you to participate in Codeforces Round 1042 (Div. 3), which will start on Aug/10/2025 17:35 (Moscow time). You will be given 2 hours and 15 minutes to solve 8 problems.

The problems are authored and prepared by -firefly-, efishel, Tobo, and __baozii__.

The round will be hosted by the 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 — rank will be determined by number of problems solved, followed by penalty; wrong submissions will incur the usual penalty of 10 minutes, following the rules of educational rounds.

As a reminder, only trusted participants of the third division will be included in the official standings table. This is a compulsory measure for combating unsporting behavior. To qualify as a trusted participant of the third division, you must:

• take part in (and solve at least one problem in) at least five rated rounds;
• and not have had 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).

Also, note the rule restricting the use of AI. If you are caught breaking this rule, you will be thrown into -firefly-'s basement. For your own well-being, I suggest adhering to the rules.

We would like to thank the following people for helping make this round possible!

• cry for his/her wonderful coordination.
• Vladosiya for translating the statements to Russian.
• No one for nutella testing.
• Dominater069, SATSKY_2025target_LGM, zeemanz, nifeshe for red testing.
• Proof_by_QED, LMeyling, Intellegent, 18o3, 0x3F, bookcat, temporary1, AksLolCoding, Maxduan for orange testing.
• wuhudsm, macaquedev, Hori, Sacharlemagne, fatalerror, reirugan, Edeeva for purple testing.
• mathtsai, Non-origination, kevlu8, chromate00, yse, hashman, _Equinox for blue testing.
• ALnQ417, white_two for cyan testing.
• SpyrosAliv for green testing.
• MikeMirzayanov for the incredible Codeforces and Polygon platforms.

Good luck!

UPD: Editorial

Hello, Codeforces!

We are proud to invite you to participate in Atto Round 1 (Codeforces Round 1041, Div. 1 + Div. 2) which will be held on Aug/07/2025 17:35 (Moscow time).

The round will be rated for everyone. You will be given 8 problems, one of which is divided into two subtasks, and 3 hours to solve them. One of the problems will be interactive, so make sure to read the guide for interactive problems before the contest.

The problems are authored and prepared by Ali_BBN, Bahamin, _R00T, eren__, sweetweasel, and me.

We would like to thank:

• Error_Yuan for his great coordination.
• Alexdat2000 for Russian translation.
• errorgorn, StarSilk for nutella testing.
• _istil, abc864197532, yuanruiqi, [MVP] LMydd0225, A_G, maomao90, AmShZ, N_z__, Keshi, zeemanz for red testing.
• arashmemar, ooscode, A_M_Namdar, radal, mohammadsam, ParsaF, Iliya_Eslahi for orange testing.
• AlefHeKaaf, Shahrad_Mirzaei, rewhile, Siyah, ParsaS for purple testing.
• theSkeleton, iliya_mon, kosar, amir_AP, Ardelion, KiaRash24, hamidh100, mathtsai, Behrad. for blue testing.
• FrontMan. for cyan testing.
• MikeMirzayanov and KAN for the great platforms.
• You for participating!

Special thanks to [MVP] LMydd0225 for his invaluable help during testing!

The scoring distribution is below.

Now, a few words from our sponsor!

At Atto Trading, we are a science-driven quantitative trading firm where engineers, quants, and researchers combine their efforts to engineer cutting-edge trading systems that execute in nanoseconds, powering decisions at the speed of light in the world’s most competitive market. Many of our team members started their journey on platforms like Codeforces. We are thrilled to announce our own round on Codeforces platform.

Follow the link below and complete the application form to explore career opportunities with us.

We prepared some exciting rewards for participants in this round.

• Rank 1: Apple MacBook + backpack + branded T‑shirt + sports bag
• Ranks 2-3: Apple iPad + backpack + branded T‑shirt + sports bag
• Ranks 4-5: Apple Watch + backpack + branded T‑shirt + sports bag
• Ranks 6-20: Backpack + branded T‑shirt + sports bag
• Ranks 21-100: Branded T‑shirt + sports bag

If we encounter difficulties delivering your gift, we reserve the right to reimburse its value in cryptocurrency

Good luck!

UPD 1: Score distribution was released!

UPD 2: Editorial

UPD 3: Congratulations to the winners!

1. ksun48

2. jiangly

3. turmax

4. tourist

5. jiangbowen

6. orzdevinwang

7. maspy

8. ecnerwala

9. Radewoosh

10. 244mhq

Hello, Codeforces! We're glad to invite you to take part in Codeforces Round 1040 (Div. 1) and Codeforces Round 1040 (Div. 2), which will start on Jul/31/2025 17:35 (Moscow time).

You will be given 6 problems and 3 hours to solve them in both divisions. Some problems will be divided into subtasks.

The problems were authored and prepared by me.

Some problems may be interactive. So please refer to the guide on interactive problems if you are unfamiliar with them.

We would like to thank

• TheScrasse and errorgorn for the coordination;
• Alexdat2000 for Russian translation;
• BurnedChicken, who impressively solved $$$15$$$ problems, for VIP++ testing;
• StarSilk, liympanda, Irmuun.Ch, irkstepanov, nifeshe, Error_Yuan, Akulyat, sevlll777, FairyWinx, IceKnight1093, Kaey, -firefly-, TopazDragon89, misteg168, DAleksa, n0sk1ll, nicolasalba, AbduSaber, masa.dobric, reirugan, raresh30, chromate00, gleb.astashkin, dimasik06 for testing;
• MikeMirzayanov and KAN for creating Codeforces and Polygon.

Good luck and have fun!

Score distribution:

• Div.1: $$$500$$$ — $$$1000$$$ — ($$$750+750+750$$$) — $$$2000$$$ — $$$3000$$$ — ($$$2500+2500$$$)

• Div.2: $$$500$$$ — $$$1000$$$ — $$$1250$$$ — $$$1750$$$ — ($$$1500+1500+1500$$$) — $$$4000$$$**

UPD 1: Editorial

UPD 2:

Congratulations to the winners!

Div.1:

Kevin114514

jiangly

ecnerwala

ksun48

EnofTaiPeople

Div.2:

alaevS

MoriorInvictus

bradley.louie1

kaiboy

Ghammaz-Hassan

🚀 Hello Codeforces — from Atto Trading!

We invite you to take part in our first round on Codeforces: Atto Round 1 (Codeforces Round 1041, Div. 1 + Div. 2). Join us on Aug/07/2025 17:35 (Moscow time) and test your skills by solving problems!

Atto — Named after 10⁻¹⁸. In our world, every nanosecond counts — trading happens faster than a blink.

Are you obsessed with optimization? Do you count nanoseconds like your code depends on it?

If so — we might have something in common. If you're passionate about low-level optimization, algorithmic thinking, and squeezing performance out of every cycle in C++, this is the kind of problem-solving you’ll love.

We’re Atto Trading, a science-driven quantitative trading firm where code is everything and every nanosecond matters.

Our team is a mix of engineers, quants, and researchers — many of whom started their journey on platforms just like this one. We engineer cutting-edge trading systems that execute in nanoseconds, powering decisions at the speed of light in the world’s most competitive market.
And we build them the same way you approach a hard Codeforces problem:

➡ With clean logic, performance in mind, and relentless iteration.

💡 Why It’s a Perfect Fit for Competitive Programmers

• We love clever algorithms, smart heuristics and clear code.
• We fine-tune for speed, precision, and even the most unexpected scenarios.
• You’ll work on systems where shaving off 50ns actually changes the outcome.
• No toy problems, only real, production-grade challenges.

🧠 What You’ll Find at Atto:

• A strong engineering culture that rewards thinking deeply and moving quickly.
• Real-world problems that are as challenging as the toughest algorithmic puzzles — but with real impact.
• Opportunities across software engineering (C++, Python), Infrastructure, Trading Operations, and Quantitative Research.
• Offices in New York, Lisbon, Kyiv.

Top The Ranks, Win The Rewards!

• Rank 1: Apple MacBook + backpack + branded T‑shirt + sports bag
• Ranks 2-3: Apple iPad + backpack + branded T‑shirt + sports bag
• Ranks 4-5: Apple Watch + backpack + branded T‑shirt + sports bag
• Ranks 6-20: Backpack + branded T‑shirt + sports bag
• Ranks 21-100: Branded T‑shirt + sports bag

If we encounter difficulties delivering your gift, we reserve the right to reimburse its value in cryptocurrency.

🎯 We’re Hiring

Whether you’re just finishing university or already an experienced professional, we’d love to hear from you.

If your Codeforces graph trends sharply upward, or if you find joy in debugging what others call "impossible" – this might just be your next challenge.

If you're interested in job offers from our company, please fill out the form:

Good luck!

Hello Codeforces!

We are glad to invite you to Codeforces Round 1039 (Div. 2), which will take place on Jul/27/2025 17:35 (Moscow time).

The problems were created by I_love_Michel_Sardou, Richem, bestial-42-centroids, Yuuuuuuuuuuuuuuuuu and me.

We would like to thank:

• Akulyat for coordinating our round and helping with the preparation of the problems.

• antontrygubO_o, Adam_GS, JeanBombeur, Error_Yuan, Everule, prvocislo, KiKoS, LMeyling, mrthimote, Jasonwei08, arknave, mcfr, madlogic, kinnikuma, raphaelp, tibinyte2006, dssfsuper2, dazlersan1 and Thyl for testing.

• MikeMirzayanov for the Codeforces and Polygon platforms.

You will have 2 hours to solve 6 problems.

Good luck!

UPD: The score distribution is 500 — 1000 — 1250 — 1750 — (1750+1750) — 4000.

UPD2: The editorial is out!

UPD3: Congratulations to the winners!

Div.1

1. 244mhq
2. StarSilk
3. platter
4. arvindf232
5. TKT_YI

Div.2

1. HusseinFarhat
2. tianbincheng
3. tw20000807
4. DrKodiererstein
5. Ar1hara_Nanami

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. Limited scholarships available — don't miss your chance to study in Europe for free!

On Jul/22/2025 17:35 (Moscow time) Educational Codeforces Round 181 (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, Maksim FelixArg Novotochinov, Polina ifive Piklyaeva and me. Also, huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

Big thanks to the testers shnirelman and Brovko for their valuable advice and suggestions!

Good luck to all the participants!

UPD: Editorial is out