Hello Codeforces!

Back from the dead, we'd like to invite you to the online mirror of the Helvetic Coding Contest, Switzerland open championship! You can find past mirror from 2019, 2018, 2017, and 2016.

The Helvetic Coding Contest used to be held yearly at EPFL. This year, the Polympiads association is bringing it back alive! The contest itself took place on April the 13th, but the online mirror is scheduled on Saturday, 4th of May, 09:05 Swiss time. The duration is 4:30.

Rules:

• you can participate in teams or individually with a single computer (1-3 people),

• standard ACM-ICPC rules (no hacking),

• the contest is not rated,

• if you have participated in the onsite contest, please do not participate in the mirror.

Contrary to what the mirror's date might lead you to believe, this year's theme is Harry Potter. It features 7 series of 3 related tasks with increasing difficulty (easy/medium/hard). Note that we do not guarantee that all problems are solvable using python.

Thanks a lot to:

• Petr, Charbel, ScarletS, 3EVEHAR_KOAVA, AdrienVannson, bjornargh, and zehnsechs for setting and/or coordinating the problemsetting,

• matrix for preparing the technical setup of the contest

• paula, Macdu, McLovinn as well as problemsetters for testing the contest,

• All of Polympiads committee and on the day staff for making the contest possible,

• MikeMirzayanov for creating the amazing Codeforces and Polygon platforms!

UPDATE: Editorial is out, also available as a PDF. Thanks all for participating!

UPDATE 2: Congratulations to the winners who solved all 21 subtasks:

1. thinking: Ormlis, Mangooste
2. Captain take me!: crazy_sea, A_zjzj, 275307894a
3. japan406364961: Nyaan, kotatsugame, risujiroh
4. Qingyu Fan Club: xinyoudui, GapGapGap, InfiniteStarlight
5. Idea Generators Club: tedi_2.0, Denisov, Valera_Grinenko
6. 244mhq
7. jiangly

UPDATE 3: Also huge congratulations to the winners of the onsite round (no prewritten code or Internet access was allowed, so the conditions were a bit different):

1. Felt smart (might un-participate later) — 20 subtasks
2. Nameless Silly Moon — 18 subtasks
3. ***IsEvil? — 17 subtasks
4. Breakfast Master Toaster — 16 subtasks
5. Hairy Stofler — 16 subtasks
6. thethingswedoforpizza — 15 subtasks
7. huchibuchi — 15 subtasks

We hope you enjoyed the problems, please share your thoughts in comments!

Hello everyone,

FBI and SashaT9 are very exited to invite you to Codeforces Round 943 (Div. 3)! It starts on May/02/2024 17:45 (Moscow time).

The format of the event will be like any Div. 3 rounds:

• 6-8 tasks;
• ICPC rules with a penalty of 10 minutes for an incorrect submission;
• 12-hour phase of open hacks after the end of the round (hacks do not give additional points);
• after the end of the open hacking phase, all solutions will be tested on the updated set of tests.

Only trusted participants of the third division will be included in the official standings table. This is a forced 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 (or you are a newcomer/unrated), then the round will be rated for you.

We would like to thank:

• MikeMirzayanov for creating Codeforces and Polygon;
• Vladosiya for coordinating the round;
• feeder1, Umanity, Do_not_make_friends, Ryougi-Shiki, MAKMED1337, EyadBT, purinliang, waipoli, ksu_, _Dragon_, royhahayayaha, OAleksa, AlphaMale06, perekopska.d, Acanikolic73, Sheikh_Sady for testing the round and making it better.

Good luck and have fun!

UPD: Editorial.

久别无恙, Codeforces!

We are glad to invite you to take part in Codeforces Round 942 (Div. 1) and Codeforces Round 942 (Div. 2), which will start on Apr/30/2024 17:35 (Moscow time). You will be given 6 problems and 2 hours and 30 minutes to solve them in both divisions. Some problems will be divided into two subtasks.

The problems were authored and prepared by N_z__, wyrqwq, yinhy09 and me rui_er.

We would like to thank:

• TheScrasse for his perfect coordination.
• Alexdat2000 for Russian translation.
• negative1, tzl_Dedicatus545 and lelml for providing some rejected problem proposals and discussing problems with us.
• peti1234 and A_G for LGM testing.
• 10circle, le0n, Clein.qwq, AC-Automation, LMydd0225 and prvocislo for red testing.
• Survivor_winner, _rey, lvkaiyi0811, heaksicn, fishy15, FzArK, Error_Yuan, golions and jamesbamber for orange testing.
• zplqwq, StudyingFather, htetgm, carnation13, purp4ever and Tricopter for violet purple testing.
• tianbincheng, dxbt, LaMatematica14, OgradL, newb_programmer, joaozao, ssshanto, Quinx and 1egend for blue testing.
• lzqy__, stalkkk_19, madsere and Alenygam for cyan testing.
• Amirben for green testing.
• acoatoitgs for gray testing.
• MikeMirzayanov for the great Codeforces and Polygon platforms.

• You

  for participating in this round.

Score distribution:

• Div. 2: 500 — 750 — 1500 — (1000 + 1500) — 2500 — 3500
• Div. 1: 750 — (500 + 750) — 1250 — 1750 — (1750 + 1000) — 3500

We hope you'll like the problemset!

UPD: Congrats to the winners!

Div. 2:

1. 3_m
2. RinaRin
3. eightniko
4. liumohan
5. golomb

Div. 1:

1. tourist
2. jiangly
3. jqdai0815
4. gamegame
5. Kevin114514

Editorial is out.

Привет, Codeforces!

Благодаря поддержке Neapolis University Pafos, продолжается серия образовательных раундов.

В 29.04.2024 17:35 (Московское время) состоится Educational Codeforces Round 165 (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 и Роман Roms Глазов. Также большое спасибо Михаилу MikeMirzayanov Мирзаянову за системы Polygon и Codeforces.

Удачи в раунде! Успешных решений!

UPD: Разбор опубликован

Hi, Codeforces!

I welcome everyone to participate in Codeforces Round 941 (Div. 1) and Codeforces Round 941 (Div. 2), which will start on Apr/27/2024 17:35 (Moscow time).

Both divisions will be given 6 problems and 2 hours to solve them.

One of the problems was also used in the Yandex Cup finals, which was authored by tourist, so if you participated in the Yandex Cup finals or know the problems, please refrain from participating. All other problems were created and prepared by me.

I would like to thank:

• tourist for creating and preparing one of the problems
• 244mhq for coordinating the round and translating statements to Russian
• AlexanderL, Brovko, errorgorn, espr1t, ezdp, ezraft, IgorI, Java, Kaitokid, kotatsugame, Leonardo16, MJavad, ScarletS, Thost, tourist, and Um_nik for testing the round
• and of course, MikeMirzayanov, for the Codeforces and Polygon platforms

Good luck to all the participants!

Score distribution:

Division 1: 500 — 1250 — 1500 — 2000 — 2500 — 3500

Division 2: 500 — 1000 — 1500 — 2000 — 2250 — 3000

Update: Editorial is up

Congratulations to the winners!

Div. 1:

1. jiangly
2. conqueror_of_tourist
3. nocriz
4. tatyam
5. bruhopen

Div. 2:

1. Chengxixi
2. SlhShn
3. SlavicC
4. awooga
5. zyh_helen

Hello Codeforces!

We're glad to invite everyone to participate in Codeforces Round 940 (Div. 2) and CodeCraft-23, which will start on Apr/21/2024 17:35 (Moscow time). The contest will be rated for all the Div. 2 participants (Rating < 2100).

The Programming Club at IIIT-H organizes this event as a part of our techno-cultural fest Felicity @ IIIT Hyderabad.

You will have 6 problems to solve in the duration of 2 hours 2 hours and 15 minutes. One of the problems is divided into 2 subtasks. Do ensure you read all of the problems!

There have been a bunch of people that have helped us in making this contest a (hopefully) great one!

• ScarletS and KAN for their wonderful coordination.
• Alexdat2000 for translating the problem statements to Russian.
• akcube, fangahawk, GenghizKhan, JadeReaper, kevaljain, keyurchd_11, lezirtin, ppt1524, Prakul_Agrawal, SilverTongue1729, shakr, TheRaja who helped with brainstorming problem ideas and preparing them.
• A_G, dorijanlendvaj, Andreasyan, MridulAhi, codelegend, prvocislo, satyam343, shiven, mwen, JagguBandar, fishy15, islingr, nor, golions, WAtoAC2001, hackerbhaiya, carnation13, Murinh0, AbhijnanVegi, freaksier for testing the round, and giving useful advice regarding problem preparation to make the contest better.
• And MikeMirzayanov for the amazing platforms, Codeforces and Polygon, which has made contest preparation an even greater experience.

Score Distribution: $$$500 - 1000 - 1500 - 1750 - 2250 - (2250 + 1250)$$$

Hope you enjoy the problems!

UPD: The editorial can be found here.

UPD: The Winners

Official

1. Alphaqwq_
2. misfits
3. Monkey1ng
4. Nanani_fan
5. lmq3z

Unofficial

1. BurnedChicken
2. maspy
3. kotatsugame
4. zdc123456
5. zjy2008

Hello Codeforces!

The 2023 ICPC World Finals Luxor will begin on April 18, 2024 at 10:00 UTC. This time, we have a double World Finals. You can distinguish them by colors: blue (fish emoji) and green (crocodile). Join us on the live broadcast for this awesome double event of the year in competitive programming; commentators will include ecnerwala, SecondThread, Egor, and more!

ICPC World Finals Luxor is hosted by The Arab Academy for Science, Technology, & Maritime Transport (AASTMT), the ICPC World Finalist teams for two seasons will compete for World Championship awards, prizes, and bragging rights. More than 130 teams of each season represent the best of great universities of eight ICPC regions.

Teams qualified to ICPC WF Luxor:

• Official list — select region
• Non-official list with CF rating: 46 47

Some useful links:

• Official website of the ICPC
• Official ICPC WF Luxor website
• Schedule of Events
• Live broadcast
• Photo Gallery
• Mirrow Contest
• ICPC World Finals Mirror (ksun48 + Petr + tourist)
• Luxor brochure

Scoreboards:

All available broadcasts:

Also, you can observe teams' monitors and web cameras on the separate broadcast. Sent team's hashtag to the chat to see your favorite! All hashtags for both seasons were collected in this list

We wish good luck to all competing teams to have a great time spending, and to do the best to get amazing results!

Привет, Codeforces!

Скоро начнется отборочный тур IX Липецкой командной олимпиады школьников по программированию, к участию в котором мы приглашаем всех желающих!

Наша олимпиада проходит уже в девятый раз. В прошлом году на финале олимпиады очно в Липецке собрались 35 команд из разных регионов России, и мы приглашаем всех желающих и в этом году!

Для начала хочется рассказать несколько новостей, касающихся нашей олимпиады. У олимпиады наконец-то появился сайт https://lscpc.ru (за который хочется отдельно поблагодарить Филиппа grphil Грибова). Также у олимпиады есть канал, куда будет публиковаться актуальная информация. На сайте уже запущена регистрация на отборочный тур. Наконец, хочется упомянуть, что всем иногородним участникам будет предоставлено бесплатное проживание и питание на базе Центра поддержки одаренных детей "Стратегия", за что можно поблагодарить компанию Яндекс!

Медалисты ЛКОШП в прошлом году

Финал олимпиады пройдет с 1 по 2 мая 2024 года в Липецке на базе Института развития образования Липецкой области. Мы приглашаем команды из других регионов приехать в Липецк и принять участие в олимпиаде очно!

Мы готовы пригласить к участию в финале от 25 до 35 команд, которым будет оплачено проживание и питание во время пребывания в Липецке. Единственное, что придется оплатить участникам самостоятельно, это проезд до Липецка. Все участники финала олимпиады получат мерч олимпиады, а призеры и медалисты, разумеется, получат призы.

Отборочный тур начнется 19 апреля в 00:00 по Московскому времени и продлится до 23:59 25 апреля по Московскому времени. Отбор и финал олимпиады проводятся на системе ejudge. Отбором является виртуальный контест длительностью 5 часов, начать который вы можете в любое удобное время до окончания отбора. Отборочный тур проходит без прокторинга, но мы настоятельно рекомендуем решать задачи самостоятельно и надеемся на честность всех участников.

Команды, в составе которых все три участника являются призерами или победителями заключительного этапа ВсОШ по информатике или медалистами ВКОШП, приглашаются к участию без написания отборочного тура.

Команда должна состоять ровно из трех человек, каждый из которых должен являться школьником на момент 1 сентября 2023 года. Разрешено формировать команды из учеников разных образовательных учреждений и разных регионов.

Для регистрации на олимпиаду вам нужно заполнить следующую форму. Перед началом тура на сайте появится возможность входа в систему ejudge. По всем вопросам можно писать в Telegram чате или на почту, указанную на сайте.

(I'm too lazy to write a post so I copied last year's, thanks pooty)

Hello, Codeforces community!

We are happy to invite you to participate in National University of Singapore (NUS) CS3233 Final Team Contest 2024 Mirror on Monday, April 15, 2024, at 09:15 UTC. CS3233 is a course offered by NUS to prepare students in competitive problem solving.

The contest is unofficial and will be held in Codeforces Gym. Standard ICPC rules (Unrated, ICPC Rules, Teams Preferred) apply. The contest is unrated. Note the unusual starting time.

The problems are written and prepared by user202729_, rama_pang, yz_, benson1029, HuaJun, and feeder1.

We would also like to thank:

• Prof. Steven Halim for coordinating and teaching the CS3233 course;
• benson1029 and HuaJun as teaching assistants;
• stack.py (Pyqe, hocky, faustaadp), and Berted for testing the contest;
• errorgorn for existing;
• the Kattis team for the platform used in the CS3233 course and in the official contest;
• Codeforces Headquarters for letting us announce on the main page; and finally
• MikeMirzayanov for the amazing Codeforces and Polygon platform!

The contest will last for 5 hours and consist of 13 problems. While it is preferred to participate in a team, individual participation is also allowed.

The problems themselves may be quite standard as they are targeted toward those who have just learned competitive problem solving. However, we have also included a few challenging problems for stronger teams, such as ex-IOI or ICPC participants taking part in the course as well. So, the participants can expect a good mix of problems of varying difficulty levels, that we hope can be educational!

We hope you will enjoy and have fun in the contest. Good luck!

UPD: The contest is over! Here is the editorial.

Ciallo, codeforces～(∠・ω< )⌒☆

We are pleased to invite you to participate in Codeforces Round 939 (Div. 2), which will start on Apr/13/2024 17:35 (Moscow time).

The problems are from Otomachi_Una and me.

This round will be rated for participants whose rating is below 2100. Participants with higher ratings may participate out of the competition.

You will be given 6 problems and 2 hours to solve them. We hope you find them interesting.

We would like to thank:

• DaiRuiChen007 and lichenghan for helping prepare this contest.
• IgorI and irkstepanov for coordinating the round.
• A_G, NemanjaSo2005, yeminghan, lunchbox, Andreasyan, lsantire, RabbieWjy, yurongyi0504, KKT_89, MinaRagy06, carnation13, Romakolesn, blitztage, qsc114, Adam_GS, Evarine and htetgm for testing.
• MikeMirzayanov for Codeforces and Polygon platforms.

Score distribution: $$$500-750-1500-1750-(1500+750)-2500$$$

Good luck on the round and high rankings to everyone!

UPD: Editorial out.

UPD: the winners

Photo of authors (unfortunately, I can't come, so my profile is shown in the picture):

UPD: The rating changes for Educational Codeforces Round 164 will be applied after this round.