Hi, Codeforces!

mesanu, SlavicG and I are very excited to invite you to Codeforces Round 944 (Div. 4)! It starts on May/10/2024 17:35 (Moscow time).

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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.

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Thanks a lot to the testers: Dominater069, nskybytskyi, ScarletS, Gheal, BucketPotato, JustJie, htetgm, Vladosiya!

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

UPD: Editorial is out!

Hello, Codeforces!

The ICPC Challenge World Finals in Luxor is approaching for some of you, and we are delighted to provide an additional exciting opportunity to compete open to all!

We are happy to invite you to the 2023 Post World Finals Online ICPC Challenge, powered by Huawei starting on May 6, 2024 at 15:00 UTC and ending on May 20, 2024 at 14:59 UTC.

In this Challenge, you will have a unique chance:

• to compete with top programmers globally

• to solve 1 exciting problem prepared by Huawei

• to win amazing prizes from Huawei!

It is an individual competition.

2023 Post World Finals Online ICPC Challenge powered by Huawei:

Start: May 6, 2024 15:00 UTC

Finish: May 20, 2024 14:59 UTC

We hope you'll enjoy this complex Challenge!

Problem

We are glad to propose to you an exciting challenge “Accuracy-preserving summation algorithm”, which is prepared by Huawei Computing Product Line.

With this challenge, we focus on summation algorithms of floating point numbers in different precisions with the goal to use the lowest possible precision without losing too much of the accuracy of the end result. This problem arises in high-performance computing as lower precision can be computed faster. At the same time it also loses accuracy faster and can even lose it completely. Finding the right balance between fast low precision calculations and higher precision intermediate summations is a challenging task on modern architectures, and you would have an opportunity to try addressing this challenge

Prizes from Huawei

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!

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.

Hello Codeforces!

The series of Educational Rounds continues thanks to the support of the Neapolis University Pafos.

On Apr/29/2024 17:35 (Moscow time) Educational Codeforces Round 165 (Rated for Div. 2) will start.

This round will be rated for the participants with rating lower than 2100. It will be held on extended ICPC rules. The penalty for each incorrect submission until the submission with a full solution is 10 minutes. After the end of the contest, you will have 12 hours to hack any solution you want. You will have access to copy any solution and test it locally.

You will be given 6 or 7 problems and 2 hours to solve them.

The problems were invented and prepared by Adilbek adedalic Dalabaev, Ivan BledDest Androsov, Maksim Neon Mescheryakov, Roman Roms Glazov and me. Also, huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

Good luck to all the participants!

UPD: Editorial is out

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!