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, Friedrich, 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, beaten_by_ai, _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, IliyaEslahi 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. zhoukangyang

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 31.07.2025 17:35 (Московское время).

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, 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, Friedrich, 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. Grok
5. Ar1hara_Nanami

Привет, Codeforces!

Благодаря поддержке Neapolis University Pafos, продолжается серия образовательных раундов. Университет предлагает получение степени бакалавра в области компьютерных наук и искусственного интеллекта со стипендиями JetBrains. Получите передовые навыки в области искусственного интеллекта и машинного обучения, которые подготовят вас к востребованным техническим карьерам. Доступно ограниченное количество стипендий. Не упустите свой шанс учиться в Европе бесплатно!

В 22.07.2025 17:35 (Московское время) состоится Educational Codeforces Round 181 (Rated for Div. 2).

Этот раунд будет рейтинговым для участников с рейтингом менее 2100. Соревнование будет проводиться по немного расширенным правилам ICPC. Штраф за каждую неверную посылку до посылки, являющейся полным решением, равен 10 минутам. После окончания раунда будет период времени длительностью в 12 часов, в течение которого вы можете попробовать взломать абсолютно любое решение (в том числе свое). Причем исходный код будет предоставлен не только для чтения, но и для копирования.

Вам будет предложено 6 или 7 задач на 2 часа. Мы надеемся, что вам они покажутся интересными.

Задачи вместе со мной придумывали и готовили Адилбек adedalic Далабаев, Иван BledDest Андросов, Максим Neon Мещеряков, Максим FelixArg Новоточинов и Полина ifive Пикляева. Также большое спасибо Михаилу MikeMirzayanov Мирзаянову за системы Polygon и Codeforces.

Спасибо тестерам раунда shnirelman и Brovko за ценные советы и предложения!

Удачи в раунде! Успешных решений!

UPD: Разбор опубликован

Hello, Codeforces!

I am proud to invite you to Order Capital Round 1 (Codeforces Round 1038, Div. 1 + Div. 2), which will be held on Jul/19/2025 17:35 (Moscow time).

The round will be rated for everyone. You will be given 7 problems and 2 hours and 15 minutes to solve them.

All problems were authored by me.

I would like to thank:

• cadmiumky and TheScrasse for coordinating the round,

• Radewoosh, arvindf232, errorgorn, Adam_GS, Errichto, -XraY-, Marcin_smu, Rafi22, SergeiFedorov, Markadiusz, Dragos, VadymKa, freak93, Andrei_ierdnA, NemanjaSo2005, fwitt, ToxicPie9, madlogic, Porumb, ivgechu, stefdasca, tibinyte2006, lIlIlIlIIll, trraian, Buek, larush, lev1106 for testing,

• Alexdat2000 for Russian translations,

• MikeMirzayanov for Codeforces and Polygon.

Score distribution:

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

Order Capital is a team of engineers and researchers with a deep passion for algorithms, clean code, and well-crafted solutions. Many of their team members have a competitive programming background — with roots in ICPC, IOI, IMO, Code Jam, and Hacker Cup — so hosting their own Codeforces round is a particularly exciting milestone. They specialize in building high-performance systems for algorithmic trading, where every nanosecond matters.

Here’s the founder’s welcome post in case you missed it — plus info on current openings.

Considering joining the team or doing an internship? Hit the link and fill out the form — they’d love to hear from you!

🏆Prizes & Surprises:🏆

• 1st–4th — 1000 USDT
• 5th — 800 USDT
• 6th — 700 USDT
• 7th — 600 USDT
• 8th — 400 USDT
• 9th — 300 USDT
• 10th — 200 USDT

But that’s not all.

Top 10 — guaranteed, plus 20 lucky participants ranked between 11 and 200 will also get our surprise merch boxes!

Good luck, have fun, and don’t forget to apply if you're looking for your next challenge!

UPD: Editorial is up.

Hello, Codeforces!

I am very excited to invite you to our contest Codeforces Round 1037 (Div. 3), which starts on 17.07.2025 17:35 (Московское время). You will be given 7 problems and 2 hours and 15 minutes to solve them.

The problems were authored by me, __rose, Pishka12, Chalishkan and I_HATE_MD_DM to solve and alter them.

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.

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.

We would like to thank:

• Vladosiya for wonderful coordination.
• Away_in_the_heavens for help with problems.
• sstrong, Wansur for red testing.
• N29, dsolunov, daukah, parkky and ImDMka for orange testing.
• newhandIe, accord, Duukh and QazLon for purple tesing.
• itz_pabloo, APMAH, Dif1rent, MaGnsi0 thespace, I_LOVE_vinnipuh01 and Makha for blue testing.
• IceHydra, 1BR444H1M, Yozhik, NexTopper and VOP-Ansish for cyan testing.
• uropeltidae, KOI and D_D for green testing.
• abylaj-shymer-2026 for gray testing.
• MikeMirzayanov and KAN for the great platforms.
• Vinton Cerf, and Robert Kahn for inventing the internet.
• You for participating!

GL HF!

Editoral is out!:

Also I would like to show you the beauty of our country's nature with the stunning backdrop of tourist Peak (3965m)!

Hello everyone!

I invite you to take part in Order Capital Round 1 (Codeforces Round 1038, Div. 1 + Div. 2).

My name is Igor Pyshkin. Throughout my academic career, I participated in a lot of programming and math competitions: I am the 2016 ACM ICPC World Champion and competed in the onsite finals of the Facebook Hacker Cup, Google Code Jam, and TopCoder Open. After completing my degree, I transitioned into a new field — high-frequency trading (HFT).

Four years ago, I founded my own HFT fund — Order Capital. Since then together with my colleagues I have been working really hard to reach the highest levels of the HFT industry. Launching this contest on Codeforces is quite special to me, as it is our first contest on the platform as a company.

I would like to thank the Codeforces team and everyone involved in the round preparation. Our internal testing team found the problems quite interesting, I hope you will enjoy them too.

We’ve prepared some cool prizes:

• Top participants will receive cash awards.
• Plus, several random participants will get surprise merch boxes.

Below you will find information about Order Capital. We are hiring and would be happy to discuss opportunities for professional growth with you.

Based in Dubai

We’re a place where:

• Olympiad minds feel at home
• Engineering culture > corporate process
• Big ideas are valued and debated

We’re looking for:

• C++ Engineers (low-latency, high-performance)
• ML Infra Engineers (Python / C++)
• Research Engineers with strong algorithmic skills

We loved working on this round and hope it’s fun for you. If you’re curious about what we do at Order Capital — we’d love to hear from you! Just fill out a quick form.

This is our debut contest — and we’ve worked hard to make it fun, fair, and memorable. We hope you’ll enjoy the experience!

GL & HF!

Hello Codeforces Once Again

After months of hard work, cry, Lilypad and I are extremely proud to welcome you to participate in EPIC Institute of Technology Round Summer 2025 (Codeforces Round 1036, Div. 1 + Div. 2) at Jul/06/2025 17:35 (Moscow time). This round is combined for Division 1 and Division 2, and it will be rated for everyone.

You will be given $$$3$$$ hours to solve $$$9$$$ problems. One problem will be split into two subtasks.

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

• satyam343 for outstanding coordination, working tirelessly with us to improve problem quality and donating his own problems to us. I cannot thank him enough.
• Error_Yuan for proposing some ideas that weren't used in the end.
• Benq, Dominater069, nifeshe, __baozii__, and Friedrich for VIP testing.
• The rest of our seemingly infinite testers: EvenImage, 244mhq, A_G, N_z__, _istil, awesomeguy856, Dragos, prvocislo, Thienu, nika-skybytska, omeganot, IceKnight1093, MridulAhi, sammyuri, LipArcanjo, rexer, JagguBandar, yoru_sacri, conjectureguy, Intellegent, trash-can, AlperenT, -firefly-, efishel, amoeba4, spike1236, AksLolCoding, alexlikemath007, lunchbox, Mox_Taest3r, rewhile, reirugan, beaten_by_ai,IceWolf898, chromate00, SpyrosAliv, pianapolataa, macaquedev, larush, DivinePunishment, Non-origination, ALnQ417, ETL, Rahuldeb5, hotfog12, TiredPsyduck, squarebh, rlin61, and last but not least Yuhang_Pan.
• Alexdat2000 for Russian translations.
• MikeMirzayanov for Codeforces and Polygon.

The scoring distribution is below.

And now a word to our sponsors: EPIC Institute of Technology

About EPIC Institute of Technology

EPIC Institute of Technology is an innovative educational project, driven by the Deltix team under the EPAM Systems umbrella. As part of EPIC — EPAM Product Innovation Center, we aim to cultivate the brightest minds and prepare them for a future in cutting-edge technology projects.

Why EPIC:

EPIC Institute of Technology is an accelerator for the best talents. Our students will acquire hands-on experience in one of the selected major programs, all of which are highly demanded right now on top projects, together with the fundamental knowledge, so indispensable for real professionals. Successful graduates will have a unique chance to jumpstart their career on the most challenging and interesting EPAM projects worldwide. You will join the community of intelligent and driven individuals and have an honor to work with and learn from them.

Here are the answers to the most common questions:

How much does education cost?

EPIC Institute of Technology is completely free. There are no fees to register for exams, tuition fees or any other hidden liabilities. The only restriction for getting into EPIC Institute of Technology is age. You must be at least 18 years old to become a student.

How is the educational process organized?

Each program lasts exactly one year. The academic year consists of two semesters. Courses in the first semester are the same for all programs. Courses in the second semester depend on the selected major program.

During the semester, students complete homework assignments and take 2 exams—a midterm and a final. The final grade a student gets for each training course depends on the quality of completed assignments and participation in practical classes.

How will the classes be held?

Lectures will be pre-recorded and available for self-study. Practical classes will be held at the specified time according to the provided schedule. Also, students will have access to a Discord server, where they can discuss topics of academic interest with teachers and other students.

In what language will I study?

All programs are in English.

How can I apply?

The admissions process is as follows:

1) Register on our platform
— You can immediately try a test contest to check your readiness and get familiar with the platform.
2) Take one entrance exam on July 20, July 26, or August 1
— You only need to pass any single exam to qualify!
— If you don't succeed on one date, you can try again on the next.
3) Automatic enrollment for all who pass any exam.

Pro tip: Check out previous exam breakdowns in our Codeforces group for extra preparation help.

What will happen after graduation?

All EPIC Institute of Technology graduates will receive a diploma, and top students will be offered the opportunity to join EPAM projects where the skills gained during their training will be in high demand.

Please visit our website to learn more about EPIC Institute of Technology and the available programs. If you have any questions, you can quickly ask them in our chat. Stay tuned to our announcement channel and LinkedIn page and never miss an update!

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

UPD: score distribution released

UPD2: https://mirror.codeforces.com/blog/entry/144382 editorial