Hello, Codeforces.

We have exciting news! Look at the logo. See the changes?

Yes, we are happy to announce our new sponsor and partner – the TON Foundation!

We appreciate their support!

The Open Network (TON) is a fully decentralized layer-1 blockchain designed by Telegram to onboard billions of users. The TON Foundation is aimed to further develop and advance the TON Blockchain and its related products for a mass audience.

Andrew Rogozov, founding member at the TON Foundation, says, "We strongly believe in the idea of competitive programming itself, because it is in the TON Blockchain DNA." The TON Blockchain protocol was designed by Nikolai Durov — who is a two-time ICPC world champion, a three-time IMO gold medalist, a multiple IOI medalist, and a co-founder of Telegram — and other winners of international competitions. Now the TON Blockchain core team consists of winners of blockchain contests held by Telegram.

The TON Foundation has already supported the CodeTON Round 1 earlier in March 2022. More than 22K users were registered, and 12K participants made at least one submission. "Codeforces is an unparalleled platform for developing the programming skills of coders all over the world. We are of one mind with the Codeforces team that such contests reveal a treasury full of talents," adds Andrew Rogozov.

I send rays of gratitude to Telegram and personally to Pavel Durov, who has supported our community for many years. With this help we have come a long way — we have run hundreds of rounds, developed the ecosystem, our community has grown hundreds of times. And we are moving forward! Support from the TON Foundation pleases with its succession.

I'm happy to announce that starting July 2022, we have the option to increase problem writer payouts. Hooray!

• Div. 2: $300;
• Div.1 + Div. 2: $600;
• sponsored round: $900.

In addition, we continue to encourage payments in cryptocurrency. In this case, we pay out +25%. I look forward to new rounds on our platform.

— Mike Mirzayanov

Hello, Codeforces! Or, as we like to say in Romania: Noi nu spunem asa ceva, Codeforces!

We are proud to finally invite you to participate in Codeforces Round #804, which will start on Monday, July 4th, 2022, 14:35 UTC You will be given 5 problems and 2 hours to solve them. We greatly recommend to read all the problems, statements are very short and straight to the point.

In this round, the theme is not Independance Day related. I know, maybe we should've made the theme "Freedom", but we are not Americans and the puns within the problems were already written.

Joining me on the problem setting panel are:

• Setters: Gheorghies Gheal Alexandru, Cozma tibinyte Tiberiu-Stefan, Voicu valeriu Mihai Valeriu

• Vip-Testers: Um_nik, antontrygubO_o, BlueDiamond, lucaperju, atodo

• Testers: LucaIlie, borgar02, freak93, $$$\,\,\,\,$$$ Ionut_Padurariu, Lemur95, FairyWinx, $$$\,\,\,\,$$$ Brodicico, apostoldaniel854, Kirill22, $$$\,\,\,\,$$$ Olympia, lavish315, Kuroni, $$$\,\,\,\,$$$ caheman, theodor.moroianu, TheScrasse, $$$\,\,\,\,$$$ 244mhq, VladHaivas0205, Tudy006, stefdasca, CaesarPP, Fanurie, elizatoma000w, mat50013, IacobTudor, codrincrismariu, Matteo.Verz, mircea_007, amcbn, mihneacazan, armand09

• Coordinator: Artyom123

Also, we would like to thank:

• intrusiv for not deserving to be publicly named
• tibinyte for being a "codechef carry".
• Gheal for getting order #804 at KFC.
• lucaperju and VladHaivas0205 for inviting some of the testers :)
• Artyom123 for captivating coordination, rejecting only Boring tasks. 9 div2Bs to be precise
• antontrygubO_o for improving one of the tasks!
• TON for supporting this round, details can be found in this post.
• MikeMirzayanov for great platforms, Codeforces and Polygon!

Here is the scoring distribution: $$$500 - 1000 - 1500 - 1750 - 2500$$$.

Good luck & have fun & the third part!

UPD1: Editorial is up!

UPD2: Winners!

Div 2:

• First_Brave_Niuniu
• fAKelyh
• ifzw
• H_stove
• Remakee

Div 1:

• SSRS_
• heno239
• jiangly
• disorientation
• noimi

Hi Codeforces!

ScarletS and I are glad to invite you to Codeforces Round 803 (Div. 2) which will be held on Jun/28/2022 17:35 (Moscow time). The round will be rated for participants with rating lower than 2100. The theme of the round will be déjà vu! (Wait, wasn't that already a theme before?)

Thanks to the people who made this round possible:

• errorgorn, for his fantastic coordination of the round;
• MikeMirzayanov, for creating the amazing Codeforces and Polygon platforms;
• KAN, for translation of the statements into Russian;
• antontrygubO_o, AmShZ, Ari, MagentaCobra, AlperenT, satyam343, Vladithur, phattd, fishy15, tenth, Surprise_Me, jampm, Yangster, Il9, ak2006, FionnKimberOShea, Codula, and bakekaga for testing the round, catching any mistakes and providing lots of valuable feedback!

Thanks to NEAR for supporting this round, details can be found in this post.

You will have 135 minutes to work on (and solve!) 7 problems. At most one of the problems will be interactive. Make sure to read this blog and familiarize yourself with these types of problems before the round!

The scoring distribution is $$$250-500-1000-1500-2000-2500-3250$$$.

Good luck, and see you on the scoreboard!

UPD: Editorial is out!

Hello Codeforces!

On Jun/25/2022 17:35 (Moscow time) we will hold Codeforces Global Round 21.

It is the third round of a 2022 series of Codeforces Global Rounds. The rounds are open and rated for everybody.

The prizes for this round:

• 30 best participants get a t-shirt.
• 20 t-shirts are randomly distributed among those with ranks between 31 and 500, inclusive.

The prizes for the 6-round series in 2022:

• In each round top-100 participants get points according to the table.
• The final result for each participant is equal to the sum of points he gets in the four rounds he placed the highest.
• The best 20 participants over all series get sweatshirts and place certificates.

Thanks to XTX, which in 2022 supported the global rounds initiative!

All problems except one are authored and prepared by me. The other problem is authored by gyh20.

We would also like to thank the following people:

• irkstepanov for coordination, and KAN for helping as well.
• gyh20, ShuiLaoshi, ilyakrasnovv, fengzhengwei, Vladithur, antontrygubO_o, Golovanov399, snowysecret, ak2006 for testing.
• MikeMirzayanov for polygon and codeforces.

Round information:

• duration: 2 hours and 15 minutes
• number of problems: 8
• score distribution: 500-1000-1500-2000-2000-2500-3250-4000

We are looking forward to your participation!

Upd Editorial https://codeforces.com/blog/entry/103479

Upd Winners!

1. ksun48
2. jiangly
3. Um_nik
4. Petr
5. maroonrk

Всем привет!

В воскресенье состоится всероссийская олимпиада школьников для 5-8 классов имени Келдыша. Удачи всем участникам! Олимпиада проходит под чутким руководством московской методической комиссии в лице GlebsHP, ch_egor, Endagorion, vintage_Vlad_Makeev, Zlobober, meshanya, cdkrot, voidmax, grphil, fedoseev.timofey и, конечно, Андреевой Елены Владимировны.

Мы рады представить Codeforces Round #802 на основе задач олимпиады. Это будет Div. 2 раунд, который состоится в 19.06.2022 12:05 (Московское время). Возможно, вы уже и раньше участвовали в раундах на основе олимпиад, подготовленных московской методической комиссией (раунды 327, 342, 345, 376, 401, 433, 441, 466, 469, 507, 516, 541, 545, 567, 583, 594, 622, 626, 657, 680, 704, 707, 727, 751, 775). Обратите внимание на нестандартное время начала раунда.

Задачи этой олимпиады были придуманы и подготовлены Siberian, _overrated_, Igorbunov, Ziware, talant, Olerinskiy под координацией fedoseev.timofey.

Также спасибо 74TrAkToR за помощь с организацией Codeforces версии соревнования и одну из задач, MikeMirzayanov за системы Codeforces и Polygon.

Также хотелось бы поблагодарить компанию Tinkoff и лично Татьяну TKolinkova Колинкову за неоценимый вклад в организацию соревнования.

Спасибо NEAR за поддержку этого раунда, подробности в этом посте.

Желаю удачи!

UPD1: Спасибо Um_nik, 244mhq, MichsSS, zarubin, TeaTime, devid, Mangooste за тестирование.

UPD2: Разбалловка: 500 — 1000 — 1500 — 1750 — 2500 — 3000

UPD3: Победители!

Div. 2:

1. teacherone
2. zsxdcfv
3. AndrescuIII
4. rhzmydd
5. Yuki991

Div. 1 + Div. 2:

1. SSRS_
2. noimi
3. Fysty
4. peti1234
5. teacherone

UPD4: Разбор

Hi, Codeforces!

We welcome everyone to take part in Codeforces Round 801 (Div. 2) and EPIC Institute of Technology Round, which will start on Jun/18/2022 17:35 (Moscow time).

The round will be rated for participants of Division 2 with a rating lower than 2100. Division 1 participants can participate unofficially in the round.

You will be given 5 problems and 2 hours to solve them. One problem will consist of multiple subtasks.

The score distribution will be 500 — 750 — 1250 — (1250+1000) — 3000.

The round was prepared by me, ki0apa, and akifpatel.

We would like to say a word of appreciation:

• to antontrygubO_o for amazing coordination of the round
• to 18o3, bobbilyking, brunovsky, BucketPotato, dbaumg, fishy15, jonathanh8686, Max_Calincu, 244mhq, naman1601, richardkyu, rivalq, satyam343, timreizin, Vladik, vilcheuski for testing the round
• and of course, to MikeMirzayanov for the Codeforces and Polygon platforms.

Good luck to all the participants!

Update: Editorial is out!

About EPIC Institute of Technology

Recently, in our blog, we have introduced the educational project of EPAM called EPIC Institute of Technology.

EPIC Institute of Technology, a part of EPIC — EPAM Product Innovation Center, is truly a unique educational project driven by the Deltix team under the EPAM Systems umbrella.

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 them are highly demanded right now on the top projects, together with the fundamental knowledge, so indispensable for real professionals. Successful graduates will have a unique chance to jump start 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 or tuition fees.

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.

Students will take an intermediate assessment in the middle of the semester. The final grade will be given for each course at the end of each semester. The grade a student gets for each training course, depends on the quality of the laboratory work and participation in lectures and practical classes.

Lectures, practical classes, seminars, conferences, and other interesting activities are provided for students on all training courses.

How will the classes be held?

All classes will be held online. Lectures and practical classes will be held at the specified time according to the provided schedule. Recordings of all classes will be available for those students who, for any reason, were not able to attend.

In what language will I study?

All programs are in English language.

What will happen after graduation?

EPIC Institute of Technology graduates will get a diploma and an offer to join, either as an intern or a full-time position, one of the hot EPAM projects where skills acquired at EPIC Institute of Technology will be demanded.

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.

Hi Codeforces!

Keshi, alireza_kaviani and I are delighted to invite you to participate in Codeforces Round 800 (Div. 1) and Codeforces Round 800 (Div. 2).

• Start time: Jun/16/2022 17:35 (Moscow time)
• Duration: $$$120$$$ minutes
• Number of Tasks: $$$6$$$ for both divisions
• Rated range: ($$$-\infty$$$,$$$1899$$$] for Div2, [$$$1900$$$, $$$\infty$$$) for Div1

We are honored to have set the 800th Codeforces round. We wish this wonderful platform all the best along with many other exciting rounds.

Huge thanks to the following people:

• antontrygubO_o for his breath-taking coordination.

• Our testers Um_nik, errorgorn, Koosha_Mv, irkstepanov, ymmparsa, sohsoh, fatemetmhr, Dorost, nor, pooya-shams, Arnch, Kahou and mosaev for testing the round and providing invaluable feedback.

• radiohead because we got inspiration from them while coming up with task names.

• MikeMirzayanov for the amazing platforms Codeforces and Polygon!

• Last but not least, to all the participants of this round!

Thanks to NEAR for supporting this round, details can be found in this post.

We have worked hard to keep the statements clean and the pretests strong!

Please read all of the problems and their notes, enjoy your time and solve as many as you can! Good luck have fun to everyone!

The scoring distributions will be announced later.

UPD: Here are the scoring distributions:

• Div. 1: 750 1000 1500 2250 2500 3000

• Div. 2: 500 1000 1500 1750 2250 3000

UPD: Editorial is out!

Hello!

I always like to think that Codeforces is not only a place where you come to compete but also a place where you can learn. Learn new things.

Two years ago, we launched the EDU subproject, a platform for publishing classes. There are already several classes, but there are so many interesting topics around!

The Codeforces team can write the platform, make the technical foundation, but it would be great to write content with the support of the community.

Thanks to the support of competitive programming alumni, we have a budget for targeted grants for the preparation of new classes in the EDU section. Hope we have new content soon!

We are looking for lesson authors who could prepare and record one or more lessons. Those who are now red or have ever been red are invited.

We assume that one lesson (class) consists of:

• 3-5 steps: break the lesson into logical parts,
• video materials explaining the topic (usually, the total duration is 60-120 minutes),
• text summary
• a thematic training set of problems with a wide range of complexity (from the most basic on this topic to quite tricky ones)
• first of all, we would like to cover the main topics of competitive programming — DP, graphs, basic data structures, etc.

Please note that we expect you to record and edit the video by yourself. Look at already recorded lessons to understand the expected format and structure of lessons. We have a rich history of teaching, so you can count on our advice and assistance in preparing lecture plans and problems. If video editing scares you, then here we can help.

We invite you to help grow the community and make history. I am sure that the recorded classes will be watched by tens of thousands of people (or more?).

The reward for recording one class is $1000.

If you are now red or have ever been red and you are interested in this offer, then fill out the form (open until June 28th).

Hello Codeforces!

mesanu, flamestorm, MikeMirzayanov and I want to invite you to Codeforces Round 799 (Div. 4)! It starts on Jun/14/2022 17:35 (Moscow time).

The format of the event will be identical to Div. 3 rounds:

• 5-8 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, and the ratings recalculated
• by default, only "trusted" participants are shown in the results table (but the rating will be recalculated for all with initial ratings less than 1400 or you are an unrated participant/newcomer).

We urge participants whose rating is 1400+ not to register new accounts for the purpose of narcissism but to take part unofficially. Please do not spoil the contest for the official participants.

Only trusted participants of the fourth 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 fourth 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 1400 or higher in the rating.

Regardless of whether you are a trusted participant of the fourth division or not, if your rating is less than 1400 (or you are a newcomer/unrated), then the round will be rated for you.

Many thanks to the testers: Neophiliatic, Qualified, sandry24, _Anurag, jampm, TimDee, Olympia, hbarp, AlperenT, BucketPotato and VIP-tester _Vanilla_.

And thanks to NEAR for supporting this round, details can be found in this post.

We suggest reading all of the problems and hope you will find them interesting!

Good Luck!

UPD: Editorial is posted!

Привет, Codeforces!

В Jun/12/2022 17:35 (Moscow time) состоится Educational Codeforces Round 130 (Rated for Div. 2).

Продолжается серия образовательных раундов в рамках инициативы Harbour.Space University! Подробности о сотрудничестве Harbour.Space University и Codeforces можно прочитать в посте.

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, Владимир vovuh Петров, Иван BledDest Андросов и Максим Neon Мещеряков. Также большое спасибо Михаилу MikeMirzayanov Мирзаянову за системы Polygon и Codeforces.

Удачи в раунде! Успешных решений!

Также от наших друзей и партнёров из Harbour.Space есть сообщение для вас:

Привет, Codeforces!

Мы рады сообщить о замечательной возможности работы и учебы с Vodafone.

Компания Vodafone Group в партнерстве с Harbour.Space University предлагает стипендии для получения степени бакалавра и магистра в области компьютерных наук, информатики, кибербезопасности и разработки программного обеспечения, а также магистра бизнес-администрирования, и опыт работы в одной из ведущих телекоммуникационных компаний Великобритании.

Vodafone Group открывает новый технологический центр в Малаге, международный центр передового опыта, посвященный исследованиям и разработке технических решений, таких как безопасные сети, разработка 5G и 6G, Open RAN, IoT, MPN & MEC и UCC для Vodafone Business, платформ и корпоративных решений.

Мы ищем различные позиции от младшего до среднего (или старшего) звена в различных областях, таких как:

• Front-end разработка
• Full-stack разработка
• Backend разработка
• Техническая архитектура
• Архитектура предприятия

ТРЕБОВАНИЯ К ОБУЧЕНИЮ

Общие требования:

• Аттестат о среднем общем образовании или диплом бакалавра (предыдущий опыт работы обязателен при подаче заявки на получение степени магистра)
• Резюме или профиль LinkedIn (ваш рейтинг Codeforces должен быть внесен в ваше резюме)
• Свободное владение английским языком (испанский приветствуется)

Требования для Frontend разработчика:

• Опыт работы в Angular не менее 1-3 лет.
• Опыт работы в React не менее 1-3 лет.
• Уверенное знание основ веб-платформ: HTML, JavaScript и CSS.
• Разработка и внедрение приложений с низкой задержкой, высокой доступностью и производительностью
• Определение/построение конвейеров CI/CD с использованием таких инструментов, как Jenkins, Sonar, Kiuwan.

Требования для Full-Stack разработчика:

• Минимум 3 года подтвержденного опыта разработки платформ (среда на основе CDI/DevOps). С одним или несколькими из следующих:
• Java SE/ Javascript
• Сценарные языки, то есть python, perl, shell scripts.
• Подтвержденный опыт работы с backend и frontend программными системами и веб-приложениями.
• Подтвержденный опыт работы с HTPP, MQTT, LwM2M, Kafka, различными базами данных (SQL и не-SQL).
• Знание облачной разработки.
• Практический опыт работы с инструментами CDI.

Требования для Java разработчика:

• Отраслевой опыт работы с программными платформами в Linux, локально и в облаке
• Хорошее понимание серверных технологий
• Сильные академические знания и профессиональный опыт разработки программного обеспечения: Java Enterprise, Oracle, Linux, Windows
• Хорошее понимание инструментов системного мониторинга и сред автоматизированного тестирования
• Опыт работы с SQL, XML, JSON и CSV
• Опыт предоставления и поддержки преобразований и API для клиентов и партнеров
• Хорошее понимание баз данных — Oracle, MongoDB, ElasticSearch.
• Хорошее понимание фреймворков Java, SpringBoot, Spring technologies
• Хорошее понимание контейнерных систем (docker) и оркестраторов (docker compose, Kubernetes) и технологий обмена сообщениями, kafka, rabbitmq
• Хорошее понимание оболочки Unix, Perl, python для выполнения задач автоматизации и обслуживания, а также среды CI/CD
• Образование на уровне бакалавра в области телекоммуникаций или смежных дисциплин с опытом разработки программного обеспечения

Желаем удачи и до встречи в следующий раз!

Harbour.Space University

UPD: Разбор опубликован