Hello, Codeforces!

We are glad to invite you to participate in Codeforces Round 1049 (Div. 2) on Sep/09/2025 17:35 (Moscow time).

You will have $$$2$$$ hours to solve $$$6$$$ problems and some problems will be divided into subtasks. The round will be rated for participants whose rating is below 2100, but higher rated users are also welcome to participate out of competition.

The problems were authored and prepared by shorya1835, Divine_Spark and wakanda-forever.

We would like to thank:

• Sugar_fan for his great coordination.
• Alexdat2000 for Russian translation.
• doofushmirtz, Dragokj03, Shubham_KV and ho-oh, for proposing problems that later weren’t included in the final set.
• Our list of testers for providing valuable feedback: fallleaves01, _istil, Andreasyan, andrei_boaca, __baozii__, IceKnight1093, Tobo, Boboge, temporary1, ButterflyDew, BiggestOtaku, Proof_by_QED, Friedrich, Darko1, satyam343, Welcome24ever, madlogic, MaxBlazeIceInk, harshith_04, weirdflexbutok, milind0110, tridipta2806, chromate00, priyanshu.p and Non-origination.
• MikeMirzayanov and KAN for the great platforms.

Good luck & have fun!

UPD: Score distribution: $$$500$$$ – $$$1000$$$ – $$$1250$$$ – $$$1750$$$ – ($$$1750$$$ $$$+$$$ $$$1000$$$) – $$$2750$$$

UPD2: Editorial has been posted.

UPD3: Congratulations to the winners!

Div. 1:

1. arvindf232
2. cn449
3. kotatsugame
4. Rubikun
5. abc864197532

Div2:

1. Astitva_the_mahaan
2. ProfaSIO
3. RGB_ICPC8
4. Tenshi_
5. expi0i

Hello, Codeforces!

We are glad to invite you to participate in Codeforces Round 1048 (Div. 1) and Codeforces Round 1048 (Div. 2) on Sep/08/2025 17:35 (Moscow time).

The round will be rated for everyone. 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 installb, wjy666, tarjen, StarSilk and 2014CAIS01.

We would like to thank:

• maomao90 for his great coordination.
• Alexdat2000 for Russian translation.
• Um_nik, EvenImage and SSerxhs for red-black testing.
• A_G, -skyline- and __baozii__ for red testing.
• fishy15, oolimry, Boboge, Nanani, shstyle. and Tobo for orange testing.
• qsmcgogo and Retired_Zhisheng for purple testing.
• Husqqqq for blue testing.
• jellybean259 for green testing.
• akqxolotl for grey testing.
• MikeMirzayanov and KAN for the great platforms.

The scoring distribution is below.

• Div. 2: $$$ 500-1000-1500-2250-(2250+750)-3500 $$$
• Div. 1: $$$ 500-1250-(1250+750)-2500-(2750+1500)-4250 $$$

Good luck to everyone! (=^･ω･^=)

UPD：Unfortunately, it was discovered very lately (2 hours after the contest began) that the statement of div2D/div1B was missing an important condition. The correct statement should include the line "The operation 2 can only be applied at most once." The statement will be corrected soon.

We believe this issue affected many participants of this round, and therefore we have to declare this round unrated. We sincerely apologize for this mistake.

https://codeforces.me/blog/entry/146176 please refer to this blog for more information on why we decided to make the round unrated, and further elaborations on how this accident happened. We are deeply sorry for disappointing everyone, and we hope for your understanding.

UPD2: Here's the editorial: https://codeforces.me/blog/entry/146172

Hello Codeforces

Thanks to these nerds for 15 winstreak on Hypixel bedwars

SpyrosAliv and I are excited to welcome you to participate in Codeforces Round 1047 (Div. 3) at Sep/07/2025 17:35 (Moscow time). You will be given $$$2$$$ hours and $$$15$$$ minutes to solve $$$7$$$ problems.

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.

The penalty for each 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 rating of 1900 or higher.

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

• Vladosiya for coordinating and Russian translations.
• sammyuri, nifeshe, Intellegent, and temporary1 for carrying me in Bedwars.
• The testers: Dominater069, __baozii__, nifeshe, satyam343, Intellegent, catgirl, Friedrich, cry, temporary1, -firefly-, efishel, 18o3, Arpa, AksLolCoding, Edeeva, reirugan, macaquedev, chromate00, pianapolataa, RobinFromTheHood, yse, Filikec, Non-origination.

• MikeMirzayanov for Codeforces and Polygon as usual

Additionally, if you are a tester of EPIC Institute of Technology Round Summer 2025 (Codeforces Round 1036, Div. 1 + Div. 2) and you are rated for Division 3, I will ask you to not participate in the round, as it is possible you have seen some tasks before.

I wish you the best of luck and I hope you enjoy the contest!

EDIT1: editorial https://codeforces.me/blog/entry/146121

Salam Codeforces!

We are glad to invite you to follow the 2025 ICPC World Finals in Baku, Azerbaijan!

The event will mark the conclusion of the 2024–2025 ICPC season. Near the 140 university teams from different countries will join the finals. After many regional contests, they will now meet in Baku to fight for the title of ICPC World Champion at the 49th ICPC World Finals.

The 2025 ICPC World Finals Baku will start on September 4, 2025 at 11:00 (UTC+4). We invite everyone to join the live broadcast of the biggest programming event of the year!

Teams qualified to ICPC WF Baku:

• Official list
• Non-official list with CF rating
• CPHoF list of teams with names

We'll be streaming the event all week, tune in to the broadcasts some exciting content!

There will be an online mirror available. Please register in advance at this link:

Also, you can observe teams' monitors and web cameras on the separate broadcast before frozen hour. Sent team's hashtag to the chat to see your favorite!

Helpful links to follow the World Finals:

• Official ICPC World Finals website
• Schedule of Events
• Live broadcast
• Photo Gallery
• Teams' submit reactions
• Brochure

Good luck to all competing teams — may you have a great experience and show your best!

The image was created with the help of OpenAI, a sponsor of the ICPC World Finals 2025.

Hello, Codeforces.

Today I arrived in Baku for the ICPC World Finals. The very first participant I met asked me if we would be doing push-ups.

Yes! This year I decided to repeat the fun event and I invite you to join the push-up challenge. It will take place on September 3rd at 18:00. The best performer will receive a prize from Codeforces! And everyone in the top 25 will get a souvenir.

If you're not ready to do push-ups, come anyway to cheer for your friends and have fun!

We'll repeat last year's format: push-ups in rounds of 25. Gradually, people will start dropping out. Whoever does the most total push-ups will be the winner! In other words, they'll hold the title of Push-up World Champion according to the ICPC World Finals version :-)

There will definitely be a livestream on my Instagram https://www.instagram.com/mikemirzayanov/. Join us online to cheer!

See you there!

UPD 1: The complete alumni schedule can be found at https://worldfinals.icpc.global/alumni.html.

Hello, Codeforces!

We, the RiOI team, are proud to invite you to participate in Codeforces Round 1046 (Div. 1) and Codeforces Round 1046 (Div. 2) which will be held on Aug/28/2025 17:35 (Moscow time).

The round will be rated for everyone. You will be given 6 problems in both divisions, where some problems will be divided into subtasks, and 3 hours to solve them. For both divisions, the number of interactive problems will not be equal to 1, so you may need to read the guide for interactive problems before the contest.

The problems are authored and prepared by Register, STUDENT0, Error_Yuan, _istil, and Alan_dong.

We would like to thank:

• Error_Yuan for his great coordination.
• Alexdat2000 for Russian translation.
• Um_nik, errorgorn, SSerxhs, dorijanlendvaj and conqueror_of_tourist for red-black testing.
• _l_l_, E_fireworks, rui_er, Markadiusz, __baozii__, lethan3, SomethingNew, YuukiS, tfg, Sana, maomao90, A_G and FairyWinx for red testing.
• NobodyThere, wangmarui, ikrpprppp, Kolychestiy, cry, hocln, Makcum888 and beaaaan for orange testing.
• madlogic, Wf_yjqd, pacha2880, Edeeva, windreaper and denk for purple testing.
• chromate00, SunsetVoice_ and Non-origination for blue testing.
• Mohamed_Saad62 for cyan testing.
• houran for green testing.
• MikeMirzayanov and KAN for the great platforms.
• You for participating!

Special thanks to __baozii__ for his help during the preparation!

The scoring distribution is below.

• Div. 2: 500 — 1000 — 1500 — 2000 — 2750 — (2250 + 1750).
• Div. 1: 500 — 1000 — 1750 — (1250 + 1250) — (3000 + 2000) — 4000.

Good luck & Have fun! (∠・ω < )⌒☆

UPD 1: Editorial was published.

UPD 2: Congratulations to the winners!

Div. 1:

1. jiangly
2. BurnedChicken
3. Nachia
4. hos.lyric
5. Kevin114514

Div. 2:

1. SirOcylder
2. SDSXC
3. XG0000
4. gongryongwang
5. hosh1zora

Hello, Codeforces!

I am glad to invite you to take part in Codeforces Round 1045 (Div. 2), which will start on Aug/26/2025 17:35 (Moscow time).

You will have $$$2$$$ hours to solve $$$6$$$ problems. The score distribution is listed below.

There will be at least one interactive problem, so make sure to read the guide for interactive problems before the contest.

The round will be rated for participants whose rating is below $$$2100$$$, but higher rated users are also welcome to participate out of competition.

The problems were authored and prepared by me. I would like to thank:

• SSerxhs for coordination and providing great ideas to improve the problem set.
• Alexdat2000 for translating the statements to Russian.
• Our list of testers for providing valuable feedback: StarSilk, BurnedChicken, Misuki, __baozii__, _istil, A_G, SorahISA, shstyle., ub33, warner1129, lunchbox, PaperCloud, Ali_BBN, fr200110217102, AceIn, madlogic, daniel071292, polarbear03617, XiaoXia.
• MikeMirzayanov and KAN for the amazing Polygon and Codeforces platforms.

Good luck & have fun!

UPD: Score distribution: $$$500 - 1250 - 1250 - 2000 - 2250 - 2750$$$.

UPD2: Editorial

UPD3: Congratulations to the winners!

Div. 1+2:

1. Hamed_Ghaffari
2. Otomachi_Una
3. potato167
4. Daniel_lele
5. Rubikun

Div. 2:

1. cly312
2. polosatic
3. Gheal
4. Transformer911
5. Timur_Kotlyarov228

Hello, Codeforces!

I'm thrilled to invite you to take part in Codeforces Round 1044 (Div. 2), which starts on Aug/24/2025 17:35 (Moscow time). You will help Steve solve $$$6$$$ of his most dastardly problems in $$$2$$$ hours. The score distribution is as follows:

$$$\,\,\,\,$$$ $$$\,\,\,\,$$$ $$$\,\,\,\,$$$ $$$\,\,\,\,$$$ $$$\,\,\,\,$$$

One of the problems may be interactive, so make sure to read the guide for interactive problems before the contest.

The 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 me. I would also like to thank:

• flamestorm for excellent and efficient coordination.
• Alexdat2000 for translating the statements to Russian.
• myst-6 for discussing some of the problems and motivating me to propose a round.
• arvindf232 for black glazed terracotta testing.
• p0tato, Serval, N_z__, Aotsuki, _istil, cadmiumky, __baozii__ for redstone testing.
• Intellegent, yud08, Jasonwei08, mwen, Friedrich, anango, Proof_by_QED for gold testing.
• madlogic, garamlee500, macaquedev for amethyst testing.
• segtreebeats, beaten_by_ai, darysani, chromate00 for lapis lazuli testing.
• vladimirfilip for waxed lightly weathered cut copper testing.
• moonpole for forgetting to test.
• MikeMirzayanov and KAN for the amazing Polygon and Codeforces platforms.

Good luck!

UPD: Editorial

UPD2: Congratulations to the winners!

Div 1+2:

1. 111445
2. Sugar_fan
3. Otomachi_Una
4. cyx
5. kotatsugame

Div 2:

1. cyx
2. TomitaMatei
3. Yahia_Emara
4. Brinton
5. dsdp

First solves:

• A: A_G in 00:00:51
• B: A_G in 00:03:27
• C: A_G in 00:12:25
• D: Azuken in 00:22:12
• E: zhenja in 00:38:11
• F: SSerxhs in 00:40:41

👋 Salam, Codeforces!

We are excited to announce that the final round of the Rayan Programming Contest will be held onsite in Tehran, from November 25–29, 2025!

All participants ranked 1-1000 in the Rayan Selection Round are invited to complete the registration form by August 25, 2025 August 27, 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 registration form. 👕

We look forward to seeing you on-site! 🎉

UPDATE (August 23): The registration summary so far is available here. The final selection process is described in this post.

UPDATE (August 26): Because of codeforces unavailability last night, the registration deadline has been extended to August 27.

UPDATE (August 29): The list of finalists for the Rayan 2025 World Finals has been announced.

Привет, Codeforces!

Команда ТГ канала @KogutIvanTutoring рада позвать вас принять участие в Codeforces Round 1043 (Div. 3) во 21.08.2025 17:35 (Московское время) — очередной Codeforces раунд для третьего дивизиона. В этом раунде будет 6-8 задач, которые подобраны по сложности так, чтобы составить интересное соревнование для участников с рейтингами до 1600. Однако все желающие, чей рейтинг 1600 и выше могут зарегистрироваться на раунд вне конкурса.

Раунд пройдет по правилам образовательных раундов. Таким образом, во время раунда задачи будут тестироваться на предварительных тестах, а после раунда будет 12-ти часовая фаза открытых взломов, после её завершения все успешные попытки будут перетестированы на успешных взломах. Мы постарались сделать приличные тесты — так же как и вы, мы будем расстроены, если у многих будут падать решения после окончания контеста.

Вам будет предложено 6-8 задач и 2 часа 15 минут на их решение.

Штраф за неверную попытку в этом раунде будет равняться 10 минутам.

Напоминаем, что в таблицу официальных результатов попадут только достоверные участники третьего дивизиона. Как написано по ссылке — это вынужденная мера для борьбы с неспортивным поведением. Для квалификации в качестве достоверного участника третьего дивизиона надо:

• принять участие не менее чем в пяти рейтинговых раундах (и решить в каждом из них хотя бы одну задачу)
• не иметь в рейтинге точку 1900 или выше.

Независимо от того являетесь вы достоверными участниками третьего дивизиона или нет, если ваш рейтинг менее 1600, то раунд для вас будет рейтинговым.

Задачи были придуманы и подготовлены частью нашей команды: fstilus, EzikBro, KotlechkovEgor, Wileyne, Friendiks, Boodoochai, pskobx

Также большое спасибо:

• MikeMirzayanov за системы Polygon и Codeforces.

• Vladosiya за координацию раунда.

• Madball, Merkurev за красное тестирование раунда.

• a.stepanov281005, AC_sahER, Proof_by_QED, cry, fangcy за оранжевое тестирование раунда.

• _IVON_, Gmacem, Escapisst, macaquedev, ego_death за фиолетовое тестирование раунда.

• EnigmaEon, margothequeen, semwin2008, Yassia, Pistol_Engineer, EduardoBrito, radodododo, Onomui за синее тестирование раунда.

• Art10em, MrYhatoh, dragoonSlayer за бирюзовое тестирование раунда.

• NeNichiy, Rasel за зелёное тестирование раунда.

• mlovbnee за серое тестирование раунда.

Всем удачи!

UPD. Разбор выложен!