Привет, Codeforces!

Крупнейшие командные соревнования Северной Евразии снова вернулись в декабрь и в очный формат. 4-7 декабря 2022 года пройдут Двадцать третья открытая всероссийская командная олимпиада школьников по программированию и чемпионат ICPC Northern Eurasia Finals.

Northern Eurasia Finals

Трансляция Таблица результатов

Студенческий командный чемпионат пройдет в среду 7 декабря. Контест по расписанию стартует в 10.00 по московскому времени. Накануне во вторник пройдет регистрация команд, а так же церемония открытия и пробный тур. Чемпионат Северной Евразии тоже проходит на нескольких площадках: Санкт-Петербурге, Барнауле, Кутаиси и Алматы.

Ссылки на таблицу результатов, а также задачи контеста разместим после старта основного тура.

За выход в финал ICPC поборются более 300 студенческих команд. Кстати, следующий финал чемпионата мира ICPC пройдет ориентировочно в ноябре 2023 года в Шарм-эш-Шейхе, и успешно выступившие в среду команды поедут именно на него. В связи с этим на нынешний сезон наложены особенные правила региональных отборов.

Если вы не участвуете в полуфинале, вы можете попробовать свои силы на задачах финала Северной Евразии в зеркале.

Постараемся внимательно следить за успехами команд и оперативно делиться с вами всеми важными новостями и ссылками. Присоединяйтесь к прямым трансляциям чемпионатов на YouTube и в VK. Делитесь своими впечатлениями с хештегами #nef и #ВКОШП

ВКОШП

Трансляция Таблица результатов Задачи

На финальный этап ВКОШП были приглашены 248 команд. Чемпионат проходит в очном формате, поэтому команда должна собраться в одной из авторизованных точек: Санкт-Петербурге, Барнауле, Сириусе, Алматы или Ереване. Санкт-Петербург примет у себя 135 команд. В Барнаул доехала 51 команда. 44 команды соберутся в Алматы. 12 команд соревнуются в образовательном центре "Сириус", и всего лишь 7 команд в Ереване.

4 декабря прошла регистрация команд и торжественное открытие олимпиады. Основной тур чемпионата начнется в понедельник 5 декабря в 10:45 по московскому времени.

Мы собрали небольшой список команд, за которыми, как с нами поделились коллеги, будет интересно наблюдать. Не стесняйтесь добавлять в комментариях своих фаворитов чемпионата.

Желаем отличного выступления участникам соревнований!

Hello, Codeforces!

Great news! Here's another opportunity to take a part in an exciting event from our main sponsor.

The contest for smart contract developers with a total prize fund of 50,000 TON begins on 2 Dec. 12:00 UTC and lasts until 23 Dec. 18:00 UTC. TON Smart Challenge #3 will be suitable for experienced developers as well as for beginners that are ready to dive into FunC.

TON Smart Challenge #3 tasks will be dedicated to the basic aspects of how smart contracts work in TON: complex manipulations with cells, organizing the storage of smart contracts, working with comments, basic cryptography and the logic of governance smart contracts.

A contest aimed at optimization of 5 smart contracts written in the FunC language native for The Open Network blockchain. The goal of the contest is to optimize contract execution cost, preserving functionality and business logic. One may find more information about development in TON here.

Register through the @toncontests_bot to be notified, when it starts, and stay up to date

Hello, Codeforces!

UPD: Challenge is over. You can find result by this link

We are happy to invite you to the great event the 45th ICPC World Finals Challenge powered by Huawei，which will start on November 17, 2022, 00:00 UTC (UTC+0).

In this Challenge, You will have a unique chance:

• to compete during 14 days online challenge;
• to solve 1 or 2 problems prepared by different business domains of HUAWEI;
• to win amazing prizes from HUAWEI!

As a special prize, HUAWEI together with ICPC Foundation will provide the travel trip to the 46th Annual ICPC World Finals in a guest role to the 2 winners (1 winner for each problem)!

Everybody is welcome to participate. It is an individual competition.

45th ICPC World Finals Challenge powered by Huawei (open to public):

Start: November 17, 2022 00:00 UTC (UTC+0)
Finish: November 30, 2022 23:59 UTC (UTC+0)

This time HUAWEI has prepared 2 challenging tasks for you from different business domains – Central Software Institute and HiSilicon. You are free to choose which problem you would like to solve, and you are also welcome to solve both problems, but please remember the total runtime of both rounds, which start simultaneously, is 14 days only. We hope you'll enjoy this complex yet very exciting Challenge!

Each problem will have own scoreboard and own prize fund, so this is a unique chance for you to win double prize for two solved problems!

Problem No 1: Parameterized Branch Instruction Stream Generation

Benchmarks are popular for estimating and comparing the performance of computer systems which has always been a challenging task faced by computer architects and researchers. However, it is known that as emerging applications evolve, benchmark characteristics drift with time and an optimal design using benchmarks of today may not be optimal for applications of tomorrow. This problem has been aptly described as: “Designing tomorrow’s microprocessors using today’s benchmarks built from yesterday’s programs”. One of the approaches for addressing these challenges is to complement application benchmark suites with synthetic benchmarks.

Program control flow generation algorithm is one of the most difficult questions for synthetic benchmarks. Hence, this problem focuses on generating program control flow for synthetic benchmarks based on MIC related to behavior of conditional branch instructions. In this question, program control flow generation is abstracted to draw a route on a directed graph. The route and the graph with MIC closest to the input will be the winner.

Problem No 2: Task Scheduling and Data Assignment

This is a problem about job scheduling and data assignment. Consider a scenario, where we want to run a complicated software project, on a computing cluster or on a multi-core heterogeneous computing chip. The computing cluster has multiple computing units of various computing power, as well as multiple memory disks with various reading and writing speed. The software project consists of many small computing tasks with inter-dependence among them. During the execution, these tasks will also produce data that need to be stores onto some memory disks. Our goal is to design an efficient task scheduling algorithm, that is able to assign the tasks to different computing units, and to store the data to different memory disks, such that the overall makespan, which is the time the finish the last task, is minimized. As you can imagine, usually when a task starts its execution, it needs to first read the necessary data from the memory disks, and when the computation completes, it will then write its own data to some memory disk for other tasks to read. This means, the schedule of tasks to computing units, and the assignment of data to memory disks are tightly connected to each other, and they will together decide the overall running time of the whole software project.

Prizes

Challenge Rules and Conditions

By participating in this Challenge, you agree to the Challenge Rules and Conditions of Participation

Good luck, we hope this will be fun!

Hello Codeforces!

The Southern and Volga Russian Regional Contest was held in Saratov State University on 22nd of November. This contest was used to qualify the teams from Southern Russia and Volga region to the Northern Eurasia Finals.

On Nov/27/2022 13:35 (Moscow time), we will conduct the online mirror of this contest. It will last for 5 hours and is best suited for teams of three people, although it is not forbidden to participate in teams of smaller/larger size. The mirror will use ICPC rules, the same as the offline contest.

I would like to express my gratitude to all other jury members: awoo, Neon, vovuh, adedalic, DmitryKlenov, dmitryme, DStepanenko, elena and kuviman. Also, big thanks to the contest testers: IlyaLos, Oleg_Smirnov, ashmelev, pashka, and especially MikeMirzayanov not only for testing the problems, but also for his excellent Polygon system, without which it would be almost impossible to prepare the competition.

As a chief judge of the contest, I hope you enjoy the problems!

Of course, the contest will be unrated.

upd: The editorial can be found here.

Hello Codeforces!

On Nov/26/2022 17:05 (Moscow time) we will host Codeforces Global Round 24. Note the unusual time of the round.

It is the sixth 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!

The problems were written and prepared by Cocoly1990, waaitg and Imakf. 👀👀👀

We would also like to thank:

• errorgorn for 🥵 and 🥶 coordination.
• KAN for translating the problems. 🥳🥳🥳
• Wolam for proposing rejected problems. 😭😭😭
• Our testers for testing and providing invaluable feedbacks: Rebelz, Sugar_fan, ShmilyTY, dXqwq, Aestas16, SSerxhs, Qiulyqwq, Leasier, Yakumo_Ran, Nanako, Celtic, JohnVictor, installb, mafailure, CuiZhenhang, lunchbox, _rey, Wolam, apeiya, mejiamejia, TomiokapEace, QAQ_QWQ, mkisic, Mahfel, luanmenglei, ak2006 and NishikigiChisato. 😋😋😋
• MikeMirzayanov for amazing platform Codeforces and Polygon. 🥰🥰🥰

Round Information:

• Duration: 2 hours and 30 minutes 🔥🔥🔥
• Number of problems: 8 problems, one split into 3 subtasks 🤯🤯🤯
• Score distribution: $$$500$$$ — $$$1000$$$ — $$$1500$$$ — $$$1750$$$ — $$$2250$$$ — $$$2250$$$ — $$$(2000+500+500)$$$ — $$$3500$$$ 🤤🤤🤤
• There is an interactive problem, so please see the guide of interactive problems if you are not familiar with it. 🤭🤭🤭

As always, hope you all gain non-negative ratings $$$\Delta$$$ in this round! 🍾🍾🍾

UPD1: Editorial

Hi again, Codeforces!

fishy15, flamestorm, ScarletS, saarang and I are glad to invite you to our second Constructiveforces round, Codeforces Round 836 (Div. 2), which will be held on Nov/25/2022 18:35 (Moscow time). The round will be rated for participants with rating lower than 2100.

Please note the unusual time!

We'd especially like to thank:

• errorgorn and KAN, for their fantastic coordination and translation of the round!

• MikeMirzayanov, for creating the amazing Codeforces and Polygon platforms!

• Our testers dorijanlendvaj, PurpleCrayon, Ari, atodo, maomao90, prvocislo, nor, AlperenT, phattd, KrowSavcik, idk321, SlavicG, tenth, Nahian9696, Beacon, nyaruhodo, _Vanilla_, MEX1, Awesome3.14, JuanPabloAmezcua, anishde85, coder_sounak, jampm, Codula, ak2006, IAmTheHazard, and bakekaga for testing the round, catching any mistakes and providing lots of valuable feedback! We tried to get a large range of testers with different coding experiences so that everybody enjoys the round.

• And you, the contestant, for taking part in and hopefully enjoying our contest!

You will have 2 hours to work on (and solve!) 6 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! You are highly encouraged to read all the problems ;).

The scoring distribution is $$$500-1000-1500-1750-2250-3000$$$.

Good luck, and see you on the scoreboard!

UPD1: Thanks to ak2006 for making video editorials for some of the problems.

UPD2: Editorial is out!

UPD3: Congrats to the winners:

Div. 1 + 2:

1. jiangly
2. SSRS_
3. kotatsugame [tie]
4. Maksim1744 [tie]
5. March_7th

Div. 2:

1. March_7th
2. is_this_Furry
3. puffins
4. DongXuelian
5. ouqI

Hello Codeforces!

mesanu, flamestorm, MikeMirzayanov and I are glad to invite you to Codeforces Round 835 (Div. 4)! It starts on Nov/21/2022 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.

We would like to thank:

• RedstoneGamer22, tibinyte, haochenkang, badlad, qwexd, nyaruhodo, Phantom_Performer, tolbi, AlperenT, Bakry, prvocislo, Gheal, keta_tsimakuridze, KrowSavcik, BucketPotato, pashka, MikeMirzayanov for testing the round!

• Max_Calincu, TimDee, MikeMirzayanov for helping with Russian translations!

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

Good luck!

UPD: Editorial is posted.

Hello, Codeforces!

Members of team EZEC are glad to invite you to participate in Pinely Round 1 (Div. 1 + Div. 2), which will start on Nov/20/2022 17:35 (Moscow time). You will be given 7 problems, one of which has a subtask, and 2 hours and 30 minutes to solve them. The round will be rated for everyone. It is greatly recommended to read all the problems.

There is at least one interactive problem, so please see the guide of interactive problems if you are unfamiliar with it.

We would also like to thank:

• Our red sun orzdevinwang, the youngest TOP10 coder in history, for illuminating our path.
• Our great emperor antontrygubO_o for cooperating and coordinating with us to make this round happen. He saved the round by contributing his problem when a problem was found similar to an existing problem.
• Our authors for providing great ideas (both rejected and accepted): orzdevinwang, dXqwq , Forever_Pursuit, SpaceJellyfish, unputdownable, RedreamMer, pigstd. Without them, the round couldn't have been prepared so quickly.
• Our testers for high-quality testing and valuable advices: Ecrade_, cmll02, Redcrown, mtw, jqdai0815, pocafup, ieeqwq, Mooos, Justcyl, do_while_true, Ari, ffao, InternetPerson10, feecIe6418, __ZMF__, dingdingsb, PubabaOnO, lqx2005, myee, louhao088088, LinkZelda, Inversentropir-36, KagamineRin, zaozao_zmx1, Promisenxt, Tom66, RedLycoris, DearMargaret, Lynkcat, zeliboba, Kostroma, iwalainz, zemen, MELNIKOFF_OLEG, AndreySergunin, _overrated_, nick.sh, oleg_smirnov2001, kokokostya, lxyb, halin.george, Endagorion, I_love_myself, SSerxhs, LMOliver, George1123, Um_nik, 244mhq, apeiya.
• MikeMirzayanov for the great systems Codeforces and Polygon.

Fun facts:

• Anton reviewed 18 problems in total.
• This is the 13th round of EZEC. Here are some previous rounds: Round 11 on Luogu, Round 12 on nowcoder.
• The team has an anime character EZEC-chan (the girl in the image), hope you like it :3
• orzdevinwang found a better solution of F the day before the contest.

This round is made possible with the support of Pinely!

Pinely is a privately owned & funded algorithmic trading firm, our main focus is set on high frequency and ultra low latency trading.

We are a team of mathematicians, programmers, engineers and computer scientists driven by the immense passion for knowledge. We constantly face various challenges such as developing strategies for trading, optimizing trading systems to achieve the lowest latency reactions to various market events, saving and processing large volumes of historical data. The work we do requires a high ability to create effective C++ code, algorithmic thinking and mathematical intuition, which attracts winners, awardees and medalists of various competitions in the respective fields such as ICPC, IMC, HITB PRO CTF and Google HashCode etc.

Find out more about us on our website pinely.com or from our employees registered here on CF.

If you want to join our team please send your CV to [email protected] or fill in the form

Top 30 contestants and 10 random contestants placed 31-100 will receive a branded Pinely hoodie :)

The statements were made as briefly and clearly as we could. GLHF!

Scoring distribution: 500 — 1000 — 1250 — 1750 — 1750 — (2500+2000) — 3500

UPD1: Editorial is out. link.

UPD2: Congratulations to the winners:

• tourist
• dorijanlendvaj
• mnbvmar
• fivedemands
• Benq
• jiangly
• maroonrk
• inaFSTream
• hitonanode
• gisp_zjz

Pinely is a privately owned & funded algorithmic trading firm that is growing by leaps and bounds. We are based in Singapore, the Netherlands and Cyprus and our main focus is set on high frequency and ultra low latency trading.

We work in synergy to create a leading-edge & robust technology with the sole aim of exceling and establishing ourselves amongst the top trading companies around the globe. Our core team constantly faces various challenges such as developing strategies for trading, optimizing trading systems to achieve the lowest latency reactions to various market events, saving and processing large volumes of historical data.

We are a team of mathematicians, programmers, engineers and computer scientists, driven by an immense passion for knowledge. The work we do requires a high ability to create effective C++ code, algorithmic thinking and mathematical intuition, which attracts winners, awardees and medalists of various competitions in their respective fields such as ICPC, IMC, HITB PRO CTF and Google HashCode etc.

At Pinely we have a flat organizational structure with a collegial environment and an idea-driven culture to stay ahead of the curve.

Find out more about us on our website pinely.com or from our employees registered here on CF.

If you want to join our team please send your CV on [email protected]

This season we are happy to hold Pinely rounds on Codeforces. The first one will take place this sunday, on Nov/20/2022 17:35 (Moscow time). The round will be rated for all contestants.

Привет! В 18.11.2022 17:35 (Московское время) начнётся Codeforces Round 834 (Div. 3) — 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. 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.

Спасибо MikeMirzayanov за платформы, помощь с идеями для задач и координацией нашей работы. Задачи были придуманы и написаны командой Университета ИТМО: MikeMirzayanov, myav, Gol_D, Aris, Gornak40, senjougaharin и Vladosiya.

Также большое спасибо: mumumucoder, Enkognit, orloffm, TeaTime, ilyamzy, Olympia, moonveil, 74TrAkToR, molney, elseecay, bigDuck, Nickir, Be_dos, OAleksa за тестирование раунда и весьма полезные замечания. Список тестеров будет пополняться.

Всем удачи!

UPD: Разбор