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Detailed →

Codeforces Round 992 (Div.2)

By Igor_Parfenov, history, 16 hours ago,


Hello!

On Sunday, December 8, 2024 at 15:35UTC+1 we will host Codeforces Round (Div.
2).

The problems were written and prepared by Igor_Parfenov.

I would like to thank everyone who made this round possible:

 * 4mda4mda, zap4eg, triple__a, Non-origination, _Israel_, ApraCadabra, FzArK,
   Dominater069, ezraft, thenymphsofdelphi, Pervushev, Arthas, Khomutov for
   testing the round and providing feedback to the problems
 * Vladithur, for coordination of the round
 * MikeMirzayanov, for Codeforces and Polygon platforms
 * All participants

This round will be rated for participants with rating lower than 2100.

You will have 2 hours to solve 6 problems.

Score distribution: 500 — 1000 — 1500 — 2000 — 2250 — 2750.

Good luck!

Full text and comments »

Announcement of Codeforces Round 992 (Div. 2)
 * 
 * +201
 * 


 * Igor_Parfenov
 * 16 hours ago
 * 29


Codeforces Round 991 (Div. 3)

By pskobx, 5 days ago, translation,


Hello! Codeforces Round 991 (Div. 3) will start at Thursday, December 5, 2024 at
15:35UTC+1. You will be offered 6-8 problems with expected difficulties to
compose an interesting competition for participants with ratings up to 1600.
However, all of you who wish to take part and have a rating of 1600 or higher,
can register for the round unofficially.

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.

You will be given 6-8 problems and 2 hours and 15 minutes to solve them.

Note that the penalty for the 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 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, then the round will be rated for you.

Problems have been created and written by our team: AVdovin, DanGolov, kbats183,
Vladosiya and pskobx.

We would like to thank:

 1. MikeMirzayanov for Polygon and Codeforces platforms.

 2. Vladosiya for coordination.

 3. EgorUlin, qsmcgogo, molney, misorin, vladmart, Blinov_Artemii for yellow
    testing.

 4. snasibov05, FBI for purple testing.

 5. artcosec, Pslnd, _icy_, Gabbasov, UniversalAdmin for blue testing.

 6. dmit_brit, WahidmShafin, Osama.Rafat100 for cyan testing.

 7. Kaushal_26 for green testing.

Good luck!

UPD: Editorial is out.

Full text and comments »

Announcement of Codeforces Round 991 (Div. 3)
 * 
 * +184
 * 


 * pskobx
 * 5 days ago
 * 233


Codeforces Round 990

By KAN, 6 days ago,


Hi Codeforces!

On Tuesday, December 3, 2024 at 07:25UTC+1 we will hold Codeforces Round 990
(Div. 1) and Codeforces Round 990 (Div. 2). Note the unusual starting time!

The harder problems of this round are based on the problems from the Final round
of Yandex Cup 2024, Algorithms track, that will be held at the same time.

The problems are authored by elshiko, Flyce, MrLolthe1st, sokolow, stepanov.aa,
TeaTime, Tikhon228, webmonster, 4qqqq with guest problems from myst-6,
Vladithur, BledDest and me.

I'd like to thank daubi, Golovanov399, arbuzick, pperm, orz, AgafonovArtem,
Qwerty1232, k1r1t0, Itsmylove1, Sofi_, and errorgorn for testing the problems,
tourist for helping with the round, and MikeMirzayanov for the Polygon and
Codeforces systems.

Because of official Yandex Cup Finals ends later than the round on Codeforces,
the upsolving, solutions, and test cases will be closed until the end of the
onsite contest, roughly 3 hours after the end of the Codeforces round. It is
also forbidden to discuss the problems publicly until the end of the onsite
round. Any comments here concerning the problems will be removed.

Good luck!

UPD: The contest has been delayed to make sure the online contest does not start
earlier than the onsite one.

Congratulations to the winners!

Div. 1:

 1. jiangly
 2. hank55663
 3. noimi
 4. cxm1024
 5. Pyqe

Div. 2:

 1. RGB_ICPC8
 2. timer2024
 3. tietieAM
 4. ylzxxx7
 5. mion_sonozaki

UPD: You are free to discuss the problems now.

UPD: Editorial.

Full text and comments »

Announcement of Codeforces Round 990 (Div. 1)
Announcement of Codeforces Round 990 (Div. 2)
 * 
 * -187
 * 


 * KAN
 * 6 days ago
 * 171


Educational Codeforces Round 172 [Rated for Div. 2]

By awoo, history, 7 days ago, translation,


Hello Codeforces!

The series of Educational Rounds continues thanks to the support of the Neapolis
University Pafos. They offer a BSc in Computer Science and AI with JetBrains
Scholarships. Gain cutting-edge skills in AI and machine learning, preparing you
for high-demand tech careers. Curious? Check out the CSAI curriculum now.
Limited scholarships available — don't miss your chance to study in Europe for
free!

On Monday, December 2, 2024 at 15:35UTC+1 Educational Codeforces Round 172
(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 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

Full text and comments »

Announcement of Educational Codeforces Round 172 (Rated for Div. 2)
 * 
 * +168
 * 


 * awoo
 * 7 days ago
 * 124


Online mirror of The 2024 ICPC Asia Jakarta Regional Contest

By Pyqe, 11 days ago,


Selamat pagi Codeforces!

We're going to hold The 2024 ICPC Asia Jakarta Regional Contest.

We invite you to join the online mirror contest 2024-2025 ICPC, Asia Jakarta
Regional Contest (Online Mirror, Unrated, ICPC Rules, Teams Preferred) on
Codeforces. It'll be held on Sunday, December 1, 2024 at 06:05UTC+1 and will
last for 5 hours.

The mirror will be held using ICPC-style scoring with 10 to 13 problems. The
problem statements will only be available in English. We encourage participating
as a team using only one computer for coding (as in ICPC contests). The mirror
will be unrated.

Some useful links:

 * The 2024 ICPC Asia Jakarta homepage
 * The regional information in ICPC Global
 * The onsite scoreboard

We hope that you'll enjoy the contest. Good luck and have fun!

UPD. The mirror has ended! You can find the editorial here. The onsite
scoreboard will be unfrozen after the closing ceremony. Thank you for
participating and we hope that you enjoyed the problemset!

UPD2. Mistake in Problem D. Aquatic Dragon

The act of activating a shrine is supposed to be mandatory once you reach an
island instead of being optional. During contest preparation, the initial
problem had a statement that implies the aforementioned obligation of shrine
activation, which the judges had a correct solution for (the one in the
editorial). However, when rewriting the problem statement for more clarity with
adjustments to the story, we ended up making it such that it's optional, without
too much thought about it, thinking it's essentially still the same problem.
Unfortunately, as we have recently found out after the contest, it's in fact not
the same problem.

The action we're taking now is fixing the statement of the problem after the
contest with the correct intended version without changing the judges' solution.
We are very sorry for the inconvenience.

Full text and comments »

Announcement of 2024-2025 ICPC Asia Jakarta Regional Contest (Unrated, Online
Mirror, ICPC Rules, Teams Preferred)
icpc, mirror, jakarta, regional
 * 
 * +174
 * 

 * Pyqe
 * 11 days ago
 * 20


Rayan 2024 Selection Round (Div. 1 + Div. 2, Rated, Prizes!)

By ArshiaDadras, 3 weeks ago,



👋 SALAM, CODEFORCES!

We are thrilled to invite you to the Rayan Programming Contest 2024 - Selection
(Codeforces Round 989, Div. 1 + Div. 2).

The Selection Round is a rated contest for Div. 1 + Div. 2, taking place on
Saturday, November 30, 2024 at 15:35UTC+1. The problems for this round were
crafted and prepared by ArshiaDadras, MohammadParsaElahimanesh, AmShZ, AmirrzwM,
and Keshi.

The top 60 trusted participants (with a maximum of three from each country) will
qualify for the onsite Final Round in Tehran, in Spring 2025. An additional
quota is reserved for the host country. Hotel accommodation, local
transportation, and meals will be provided to all finalists. More details about
the final contest will be available on the Rayan website.

🏆 SELECTION ROUND PRIZES:

 * The top 50 participants will receive T-shirts. 👕
 * Additionally, 50 random participants from ranks 51-1000 will also receive
   T-shirts.

🏅 FINAL ROUND 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

🙏 SPECIAL THANKS:

We would like to extend our deepest gratitude to:

 * MikeMirzayanov for enabling this event through the amazing Codeforces
   platform.
 * The one and only KAN for his invaluable support in hosting the round.
 * Dear TheScrasse for his dedicated coordination efforts and lots of
   discussions about the problems and rejecting a big chunk of our problems for
   Problem C. He also contributed some problems to the contest, one of which was
   selected by the team!
 * Our testers who tested and provided invaluable feedback to improve the
   problems: peti1234 for being our LGM (VIP) tester, wyrqwq for his great ideas
   and ignoring his school midterms to test the problems, Error_Yuan for helping
   us and picking on tough problems for no reason, Hyperbolic, DylanSmith,
   valeriu, Clan328, powervic08, CepryH9, mispertion20, PineapplesOnPizza,
   vyshniak.n, ErrorAssassin, nicolasalba, naniim, estoy-re-sebado, mika_uwu,
   rulerofcakes, AkiLotus, Random_3652, sleepwalking643, Leonardo_Paes,
   RockSnow, waidenf, and newb_programmer.
 * Prof. Hamid Zarrabi Zadeh and Prof. Mohammad Ali Abam, whose leadership and
   organizational efforts make this event a reality. Thanks to their vision,
   Rayan is becoming one of the largest competitive programming contests in
   terms of prizes (and soon participants!).
 * You for participating and getting positive delta (and maybe the final prize
   in the next year 💸😉).

📊 Score distribution:
500−750−1500−1500−2000−(2000+2000)−(3000+3000)−5000500−750−1500−1500−2000−(2000+2000)−(3000+3000)−5000

We look forward to seeing you both online and onsite!

Good Luck & Have Fun! 🎉

Note: Editorial just published here! 🚀🍿

Full text and comments »

Announcement of Rayan Programming Contest 2024 - Selection (Codeforces Round
989, Div. 1 + Div. 2)
rayan, contest, onsite, announcement
 * 
 * +527
 * 

 * ArshiaDadras
 * 3 weeks ago
 * 210


2024 ICPC Asia Taichung Regional Contest [Online Mirror, ICPC Rules]

By tmt514, history, 2 weeks ago,


Hello Codeforces!

I am pleased to invite you to participate in 2024 ICPC Asia Taichung Regional
Contest (Unrated, Online Mirror, ICPC Rules, Preferably Teams), which will be
held on Sunday, November 24, 2024 at 08:05UTC+1. This is an online mirror
contest for the 2024 ICPC Asia Taichung Regional Contest, and the official
offline contest was conducted on November 17th, 2024. The duration of the
contest will be 5 hours and the contest is best for teams of three people. The
mirror will use the ICPC format.

The contest tasks are proposed by the task authors (baluteshih, waynetuinfor,
skylinebaby,samsam2310, hank55663, ltf0501, Jeffrey, Shik, tmt514, Bangye Wu,
kasuistry, and Peter Rossmanith), prepared and polished by the judge team
(Regional Contest Director Ling-Ju Hung, Chief Judge Peter Rossmanith,
kasuistry, Hung-Lung Wang, baluteshih, waynetuinfor, hank55663, cthbst, Sylveon,
CindyLinz, marmot0814, tmt514), and tested by the tester team (olmrgcsi, oToToT,
jeeeerrrpop, nikilrselvam, Vince729, applepi216). The judges appreciate the
testers for their valuable feedback!

We would like to thank MikeMirzayanov for creating the greatest Codeforces
platform, and many, many, many helps for making this online mirror contest
possible!


This is a photo of the contest venue. Photo Credit: Prof. Jinn-Shyong Yang.

On behalf of the 2024 ICPC Asia Taichung Regional Contest Judge Team, we hope
you enjoy this contest and have fun!

Of course, this contest will be unrated.

Updated: the editorial has been released! Please refer to the link in the
contest's local website.

Full text and comments »

Announcement of 2024 ICPC Asia Taichung Regional Contest (Unrated, Online
Mirror, ICPC Rules, Preferably Teams)
 * 
 * +282
 * 

 * tmt514
 * 2 weeks ago
 * 44


CodeTON Round 9 (Div. 1 + Div. 2, Rated, Prizes!)

By YouKn0wWho, 2 weeks ago,


কি অবস্থা ব্রো? আবারও চলে এসেছি! (That's Bengali for "What's up bro? I am back
again!")

I am super excited to invite you to participate in CodeTON Round 9 (Div. 1 +
Div. 2, Rated, Prizes!) which will be held on Saturday, November 23, 2024 at
15:35UTC+1. This round is rated for both divisions.

The contest will feature 88 problems, with three of them divided into two
subtasks each. You will have 33 hours to solve as many as you can. The problems
are authored and prepared by me and wuhudsm.

I would like to thank -

 * TheScrasse and Kaey for their jaw-dropping (literally) coordination of the
   round, giving valuable feedback and improving lots of problems.
 * wuhudsm for being kind enough to use one of his cool problems in the round.
 * Alpha_Q and Raiden for discussing tons of problems with me and improving some
   problems.
 * antontrygubO_o for sacrificing his TON by not participating in the round as
   he knows some of the problems as my past coordinator.
 * dorijanlendvaj, wyrqwq, Alpha_Q and nfssdq for being our MVP testers and
   improving the round immensely.
 * Thienu, wuhudsm, jdurie, Farhan132, Soumya1, redpanda, LMeyling, upobir,
   AlephZero01, NemanjaSo2005, tb_ro, Kawchar85, waidenf, serotonin, dazlersan1,
   I_Love_you_Tithi, Random_3652, Raiden and LipArcanjo for testing and
   improving the round as well.
 * redpanda for creating awesome Manim video editorials for some of the
   problems.
 * The great MikeMirzayanov for the amazing Codeforces and Polygon platforms.
 * You, for existing and participating in the round. Also, thanks for giving
   your best and not quitting. You will get what you want prettyyy soon. Just
   hold right there .

Score distribution:
500−1000−(1000+1500)−2000−2750−(2000+2000)−4250−(2250+2500)500−1000−(1000+1500)−2000−2750−(2000+2000)−4250−(2250+2500)

Wishing you TONs of luck — hope you have a TON of fun cracking the problems!

UPD: Editorial

UPD: Congratulations to the winners!

 1.  orzdevinwang
 2.  tourist
 3.  Rewinding
 4.  Kevin114514
 5.  maspy
 6.  Radewoosh
 7.  ksun48
 8.  jiangly
 9.  cn449
 10. maroonrk

--------------------------------------------------------------------------------

And here is the information from our title sponsor:



Hello, Codeforces!

We, the TON Foundation team, are pleased to support CodeTON Round 9.

The Open Network (TON) is a fully decentralized layer-1 blockchain designed to
onboard billions of users to Web3.

Since July 2022, we have been supporting Codeforces as a title sponsor. This
round is another way for us to contribute to the development of the community.

The winners of CodeTON Round 9 will receive valuable prizes.

The first 255 participants will receive prizes in USDT cryptocurrency in the TON
network:

 * 1st place: 2,560 USDT
 * 2–3 places: 1,280 USDT each
 * 4–7 places: 640 USDT each
 * 8–15 places: 320 USDT each
 * …
 * 128–255 places: 20 USDT each

All participants will receive Soulbound Tokens (SBT) that reflect their
developer rating

We wish you good luck at CodeTON Round 9 and hope you enjoy the contest!

Full text and comments »

Announcement of CodeTON Round 9 (Div. 1 + Div. 2, Rated, Prizes!)
 * 
 * +70
 * 

 * YouKn0wWho
 * 2 weeks ago
 * 211


OCPC 2025 Winter Singapore Mirror Camp

By errorgorn, 3 weeks ago,


Hi everyone!

For the Winter 2025 edition of the Osijek Competitive Programming Camp (OCPC),
we are working with the National University of Singapore (NUS) to host a mirror
of the OCPC in Singapore, during 22-26 Feb 2025. The mirror will consist of 4
training contests, that are a subset of the main 7 contest of the OCPC
(scheduled for 15 Feb-23 Feb 2025 in Osijek, Croatia and online, will be
officially announced later).

The contest days will be on 22, 23, 25 and 26 Feb, and 24 Feb will be a rest
day. The mirror takes place right before ICPC APAC Championship 2025, scheduled
for 27 Feb-2 Mar, and is a good training opportunity for its participants.
Please note that the mirror is a private initiative of NUS and OCPC, and is not
an official part of the ICPC event.

If you want to get a feel of the contests, refer to this comment for past public
OCPC contests.

We are still looking for problem-setters for this edition's OCPC. If you are
interested in problem-setting, please contact adamant. We are especially
interested in problem-setters who can come onsite to give live editorials. Refer
to this post for more details.


REGISTRATION

The participation fee for the mirror is 50 SGD per person, and it is only
possible to participate in person. Please note that it does not include travel,
accommodation or meal expenses. If you want to participate, please register here
before 10 Feb 2025.


FAQ

Will the contest system be the same as the ICPC APAC Championships?
You will use the same physical set-up, but we will be in a different room in
NUS. The online judge used will also very likely be different.

Are teams that are not attending the ICPC APAC Championships allowed to come?
Yes, you are welcome to come.

What is included in the costs?
In addition to the contest system and problems, snacks and a final dinner will
be included in the costs. Again, it does not include travel, accommodation or
meal expenses.

If you have any other questions, please write them in the comments below!

Full text and comments »

ocpc
 * 
 * +192
 * 

 * errorgorn
 * 3 weeks ago
 * 0


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