Codeforces celebrates its 15th anniversary! <img src="https://assets.codeforces.com/files/codeforces15.jpg" style="width:250px; float:right; margin: 0 1em 1em 1em;" /> Hi, Codeforces! Around this time, 15 years ago, I was deploying the first version of Codeforces on a server, registering my account, and writing the first post. 15 years have passed. Well, happy anniversary to us! For me, this is the most exciting adventure — full of ups and downs, hard work, and moments of joy. What's amazing is that it was never a lonely journey. I've always had caring and reliable friends by my side! That includes the Codeforces team, coordinators and problem writers, our partners in various events, all community members, and, of course, our sponsors — steadfast supporters and helpers. Look at what we've accomplished together! Here are some of the key metrics over the years. There seems to be plenty to celebrate! <center> <img src="https://assets.codeforces.com/files/15/01-submissions.png" class="resource" style="width:300px;"/>...

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Codeforces: Results of 2023 [Annual Report] Hello, Codeforces. Let's recall 2023, shall we? In this post, I want to summarize this year. You know, a lot of terrible things happen in the world, and personally, this year was the hardest and most sorrowful for me. But today, we'll remember something else. We'll remember what this year was like for Codeforces. Recently, Codeforces turned 14 years old. Not bad, right? And for many years now, when asked "What is Codeforces?" the first thing I say is — it's a community! [cut]<br/> #### Personal Thanks! On behalf of the community (and myself), I say thank you to everyone who tries, helps, and makes efforts to keep the community alive. Thank you to the developers! Although I continue to engage in development and other technical activities, I'm glad that these guys made an effort and improved the platform: [user:geranazavr555,2024-02-04], [user:unreal.eugene,2024-02-04], [user:vbandurin,2024-02-04], [user:ChurakovaAlexandra,2024-02-04], [user:medvezhonokok,2024-02-04]...

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CodeTON Round 5 (Div. 1 + Div. 2, Rated, Prizes!) **Note the unusual start time of the round.** Hello, Codeforces! Now that Gaokao is over, we are very glad to invite you to participate in [contest:1842], which will start at [contest_time:1842]. You will be given **9 problems** and **3 hours** to solve them. The round will be rated for everyone. All problems are written and prepared by [user:Gary2005,2023-06-21], [user:Asuka,2023-06-21], [user:Crying,2023-06-21], [user:sjcsjcsjc,2023-06-21], [user:MonkeyKing,2023-06-21], [user:DerekFeng,2023-06-21], [user:KbltQaQ,2023-06-21], [user:ShmilyTY,2023-06-21] and me. Statements and editorials will be available in Chinese (Simplified) after the contest. We would like to give our sincere thanks to: - [user:errorgorn,2023-06-21] for his wonderful coordination! - [user:Alexdat2000,2023-06-21] for translating problem statements. - [user:gyh20,2023-06-21], [user:wangziji,2023-06-21], [user:flowerletter,2023-06-21], [user:themoon,2023-06-21], [user:qiuzx,2023-06-21], [user:Gezh...

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Code Weekend #1 <div align="right" margin="20px"> <img align="right" src="/predownloaded/72/f1/72f1f31badb1452243838a0fc2553c04accff164.jpeg" alt="logo" width="300px" height="300px" margin="20px"/></div> Всем привет! Мы, команда [RGBTeam](https://clist.by/team/Romka,tourist,%E2%88%A83886090/) ([user:qwerty787788,2024-05-21], [user:Romka,2024-05-21] и [user:tourist,2024-05-21]) очень любим эвристические соревнования по программированию и очень грустим из-за того, что с каждым годом их становится всё меньше и меньше. И вот, как-то однажды мы подумали, что хватит это терпеть, и решили организовать своё соревнование :) Несмотря на то, что часто такие идеи остаются лишь идеями, в этот раз мы были полны решимости довести дело до конца и сейчас хотим пригласить вас всех поучаствовать в первом и, хочется надеяться, не последнем **[Code Weekend #1!](https://codeweekend.dev)** Соревнование пройдёт в формате, довольно близком к ICFPC/Hashcode &mdash; будет дана одна задача и несколько десятков тестов к н...

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CodeTON Round 2 Hello, Codeforces! A wonderful summer holiday! After College Entrance Examination, we are extremely delighted to invite you to our second round, [contest:1704], which will be held on [contest_time:1704]. **Note the unusual start time of the round.**You are given **8 problems** and **2.5 hours** to solve them. All problems were written and prepared by [user:Cirno_9baka,2022-07-23], [user:CoupDeGrace,2022-07-23], [user:Heltion,2022-07-23], [user:ODT,2022-07-23], [user:Yakumo_Ran,2022-07-23], [user:farmerj,2022-07-23], [user:flowerletter,2022-07-26], [user:izlyforever,2022-07-23], [user:kuangbin,2022-07-23], [user:mejiamejia,2022-07-23], [user:ugly2333,2022-07-23] and me. Task statements and editorials will also be available in Chinese (Simplified) and Chinese (Traditional) after the contest. We are sincerely thankful for the help provided by: - [user:3.141592653,2022-07-25], [user:emorgan5289,2022-07-25], [user:errorgorn,2022-07-25], [user:SevenDawns,2022-07-25], [user:pr...

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Codeforces Sponsored by TON! <img src="/predownloaded/12/a0/12a02d5f16863f9f45bba4c6cd4224f0f2178b94.png" style="float:right; margin: 0 1em 1em 1em; width: 400px;"/> 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, "<i>We strongly believe in the idea of competitive programming itself, because it is in the TON Blockchain DNA.</i>" 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...

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CodeTON Round 7 (Div. 1 + Div. 2, Rated, Prizes!) Hello Codeforces, We are very glad to invite you to participate in [contest:1896], which will start on [contest_time:1896]. You will be given **8 problems** and **2.5 hours** to solve them. The round will be rated for everyone. All the problems are written and prepared by [user:lanhf,2023-11-22], [user:Mike4235,2023-11-22], [user:thenymphsofdelphi,2023-11-22], [user:xuanquang1999,2023-11-22] and me. We would like to give our sincere thanks to: - [user:errorgorn,2023-11-22] for his wonderful coordination! - [user:Alexdat2000,2023-11-22] for translating problem statements. - [user:Um_nik,2023-11-22] and [user:conqueror_of_tourist,2023-11-22] for Legendary Grandmaster testing. - [user:jeroenodb,2023-11-22], [user:Kuroni,2023-11-22], [user:dario2994,2023-11-22] and [user:dreamoon_love_AA,2023-11-22] for International Grandmaster testing. - [user:generic_placeholder_name,2023-11-22], [user:MofK,2023-11-22], [user:minhcool,2023-11-22], [user:dvdg6566,2023-11-22] and [user:mag...

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CodeTON Round 4 (Div. 1 + Div. 2, Rated, Prizes!) Hello, Codeforces! I'm very glad to invite you to participate in [CodeTON Round 4 (Div. 1 + Div. 2, Rated, Prizes!)](https://codeforces.me/contests/1810), which will start on [contest_time:1810].You will be given **8 problems** and **2 hours** to solve them. The round will be rated for everyone. I'd like to give my sincere thanks to: * [user:74TrAkToR,2023-03-29] for the wonderful coordination! * [user:Sulfox,2023-03-29] for the help with the statements. * [user:Suika_predator,2023-03-29], [user:SSerxhs,2023-03-29], [user:LLL_2820,2023-03-29], [user:xay5421,2023-03-29], [user:NemanjaSo2005,2023-03-29], [user:applese,2023-03-29], [user:bxhnb,2023-03-29], [user:fr200110217102,2023-03-29], [user:Sulfox,2023-03-29], [user:CCSU_DZX,2023-03-29] [user:PaperCloud,2023-03-29], [user:CedeaT0,2023-03-29], [user:Kath1031,2023-03-29], [user:jcccc,2023-03-29], [user:dyxg,2023-03-29], [user:tzc_wk,2023-03-29], [user:xiaoziya,2023-03-29], [user:qiqi20021026,2023-03-29], [user:Pointy,20...

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CodeTON Round 8 (Div. 1 + Div. 2, Rated, Prizes!) Hello Codeforcers! ================== We are pleased to invite you to participate in [contest:1942]. This round will start on [contest_time:1942] and will be **rated for all participants**. There will be $8$ problems to be solved in $3$ hours, with one divided into two subtasks. Similar to [USACO](https://usaco.org/), you will help Farmer John and his cows resolve a series of first world problems. Be there or be square. This round was cooked up by [user:smax,2024-03-10], [user:sum,2024-03-10], [user:oursaco,2024-03-10], [user:cry,2024-03-13], and [user:buffering,2024-03-10]. We would like to thank the following people for making the round possible: - Our favorite cherry [user:TheScrasse,2024-03-10] for the wonderful and speedy coordination. - Our MVP testers, [user:Benq,2024-03-10], [user:Geothermal,2024-03-26], and [user:rainboy,2024-03-26], for dedicating so much time to reviewing problems, providing essential feedback, and perfecting the problemset. - The rest of ...

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CodeTON Round 3 (Div. 1 + Div. 2, Rated, Prizes!) Hello, Codeforces! Or, as we like to say in Romania: Nu îmi amintesc să fi adresat întrebări, Codeforces! I am glad to finally invite you to participate in [contest:1750], which will start on [contest_time:1750]. You will be given **8** problems and **2 hours and 30 minutes** to solve them. It is greatly recommended to read all the problems, **statements are short and straight to the point**. I would like to thank: - [user:Artyom123,2022-10-31] for prodigious coordination. - [user:AquaMoon,2022-10-31], [user:mejiamejia,2022-10-31], [user:ugly2333,2022-11-05], [user:Ecrade_,2022-10-31] for huge help in preparation and authoring one of the tasks. - [user:errorgorn,2022-10-31] for being a VIP-tester. - [user:Lemur95,2022-10-31], [user:Gheal,2022-10-31], [user:Perpetually_Purple,2022-10-31], [user:Everule,2022-10-31], [user:IacobTudor,2022-10-31], [user:andrei_boaca,2022-10-31], [user:lucri,2022-10-31], [user:AlperenT,2022-10-31], [user:Kuroni,2022-10-31], [user:pra...

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CodeTON Round 6 (Div. 1 + Div. 2, Rated, Prizes!) ### Hello, Codeforces! [user:SomethingNew,2023-09-16] and I are glad to invite you to [contest:1870], which will take place on [contest_time:1870]. You will have 2 hours 15 minutes to solve 8 problems. The round will be rated for everyone. We would like to thank: - [user:74TrAkToR,2023-09-16] for coordinating this round. - [user:isaf27,2023-09-16], [user:ugly2333,2023-09-16], [user:DataStructures,2023-09-16], [user:Little09,2023-09-16], [user:bashkort,2023-09-16], [user:Kieray,2023-09-16], [user:fishy15,2023-09-16], [user:Vladithur,2023-09-16], [user:Dart-Xeyter,2023-09-16], [user:pakhomovee,2023-09-16], [user:makrav,2023-09-16], [user:meowcneil,2023-09-16], [user:127.0.0.1,2023-09-16], [user:Nanani,2023-09-16], [user:nnv-nick,2023-09-16], [user:SomethingDifferent,2023-09-17], [user:vl342,2023-09-16], [user:shiv_codegen,2023-09-17], [user:M1lkas,2023-09-16], [user:allmath,2023-09-16], [user:sdyakonov,2023-09-17] for testing the round and providing useful feedback. - [user:Mike...

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CodeTON Round 1 (Div. 1 + Div. 2, Rated, Prizes!) Hello! It is a pleasure to invite you to [contest:1656]! The round will take place on [contest_time:1656]. The round will be **rated** for all participants. The problems of the round were authored by [user:FelixMP,2022-03-20], and they were prepared by [user:FelixMP,2022-03-20] and [user:xpov1LL,2022-03-20]. I would like to thank the following people: - [user:Baqtraqking,2022-03-20] for having the idea of preparing a Codeforces Round and helping with the solution to one problem; [user:Baqtraqking,2022-03-20], [user:izanbf,2022-03-20] and [user:xpov1LL,2022-03-20] for early help and discussion of problems, and [user:Baqtraqking,2022-03-20], [user:xpov1LL,2022-03-20] and [user:OneStone,2022-03-20] for proposals that did not make it to the final problem set. - [user:74TrAkToR,2022-03-20] for coordination of the round. - [user:MikeMirzayanov,2022-03-20] for the great platforms Codeforces and Polygon. - [user:Um_nik,2022-03-20], [user:Monogon,2022-03-24], [user:AlexLuchianov...

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CodeTON Round 9 (Div. 1 + Div. 2, Rated, Prizes!) 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 [contest:2039] which will be held on [contest_time:2039]. This round is rated for both divisions. The contest will feature $8$ problems, with three of them divided into two subtasks each. You will have $3$ hours to solve as many as you can. The problems are authored and prepared by me and [user:wuhudsm,2024-11-20]. I would like to thank - - [user:TheScrasse,2024-11-20] and [user:Kaey,2024-11-20] for their jaw-dropping (<strike>literally</strike>) coordination of the round, giving valuable feedback and improving lots of problems. - [user:wuhudsm,2024-11-20] for being kind enough to use one of his cool problems in the round. - [user:Alpha_Q,2024-11-20] and [user:Raiden,2024-11-20] for discussing tons of problems with me and improving some problems. - [user:antontrygubO_o,2024-11-20] for sacrificing his TON by not participating in the ro...

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TON Smart Challenge #5 Is Here! <img alt="TON Smart Challenge" src="https://society.ton.org/_next/image?url=https%3A%2F%2Fstorage.googleapis.com%2Fton-strapi%2FTON_Smart_Challenge_4_18e83679cf%2FTON_Smart_Challenge_4_18e83679cf.png&w=1080&q=75" style="float:right;height: 200px; margin: 10px; max-width:1000%;"/> Hello, Codeforces! I'm happy to invite the Codeforces community to join an unusual competition organized by our title sponsor, the [TON Foundation] (https://ton.org/). The competition will revolve around programming smart-contracts in FunC, native to the TON ecosystem. We invite the Codeforces community to participate in this contest and show that they can not only solve algorithmic problems in rounds but also delve into a new and interesting area. **Join the contest and master complex cell manipulations, smart contract storage organization, comment handling, basic cryptography, and the logic of governance smart contracts through problem-solving.** <center style="margin:2.5em;"> <a href="http...

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MaraTON Challenge 1 Hello, Codeforces! I'm excited to invite you to participate in [contest:2054], our first marathon in collaboration with the TON Foundation. It's great to see our partnership with TON thriving and moving forward. <p style="margin: 2em;"> <center> <a style="background-color: #3B5998; border: 2px solid #1A237E; padding: 5px 10px; color: white; font-weight: bold; text-decoration: none;" href="/contests/2054">Take part in the challenge &rarr;</a> </center> </p> The challenge is brought to you by TON blockchain engineers, some of whom are community members. Special thanks to [user:SpyCheese,2024-12-20] for preparing the problem! The competition will run for three weeks, starting on [contest_time:2054]. Get ready to dive deep into the technical details of the blockchain world — it's worth it. Winners will receive amazing prizes: - 1st place: 8,000 USDT - 2nd place: 5,000 USDT - 3rd place: 3,000 USDT - 4th–10th places: 2,000 USDT each - 11th–20th places: 1,000...

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TON Tact Smart Challenge #2 **Update:** TON Tact Smart Challenge #2 has been postponed. More information [here](https://t.me/toncontests/159). **Please note:** [contest:1942] will take place as scheduled. We will be glad to see you among the participants! <img alt=" TON Tact Smart Challenge #2" src="/predownloaded/1e/00/1e0039a5243e3f68b55784e99b93965235523618.jpg" style="float:right;height: 300px; margin: 10px; max-width:1000%;"/> Hello, Codeforces! Have you heard about **TON Tact Smart Challenge #2**? It's an amazing competition organized by our title sponsor, the [TON Foundation] (https://ton.org/) in their ecosystem. This challenge is designed to engage participants in creating a **decentralized social network** prototype utilizing the Tact smart contract language. The project consists of five stages, each aimed at implementing a core feature of the social network, from user profiles to decentralized management. We encourage the Codeforces community to participate in this contest. Dive dee...

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About CodeTON Round 1 Prizes <img src="/predownloaded/ce/9f/ce9f87d5c429f47e7691bef3a8934ebf36af3f15.jpg" style="width:250px;float:right;margin:0 1em 1em 1em;"/> **TLTR:** <i>If you are in the top-1000 of CodeTON Round 1, then fill out the form by the link https://codeforces.me/userForm/203c74605996e40f. Also, anyone who solved at least one problem in the round can fill out it and get 1 TON airdrop. The deadline is 23:59:59 (UTC +3) 04.04.22.</i> Hello. Great news from the TON Team. I give them the floor. Good news everyone! We decided to celebrate the successful finish of the CodeTON round by airdropping all the people who have solved at least one of the problems (officially, practice and virtual participation don't count) of the CodeTON round. Such participants are eligible for 1 TON airdrop and a memorable NFT. Please do note that such NFT bears only symbolic value and is not entered to have any financial or investment value. Please submit your TON wallet address via the link https://codeforces....

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TON Smart Challenge #2 <img alt="TON Foundation" src="https://codeforces.me/predownloaded/62/8f/628f11a5c33c9a826d89e1d53801d4c6141ea2dd.jpg" style="float:right;height: 300px; margin: 10px; max-width:50%;"/> _Hello, Codeforces!_ _Take a look on excellent news from [TON Foundation](https://ton.org/) about TON Smart Challenge._ _Please note that this contest will not take place on Codeforces. It is about smart-contracts, not traditional algorithmic problems. But in the last similar competition, the competitive programmers were among the winners!_ _I pass the floor to the TON team._ The next edition of the TON Smart Challenge contest for programmers is slated to begin on Aug. 4 with a total prize pool of **16,000 Toncoin**. TON Foundation developers have carefully reviewed and considered feedback from participants of the first TON Smart Challenge and will make quality-of-life improvements for the upcoming second part of the competition. The TON Smart Challenge #2 is aimed at developers jus...

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How could we receive USDT in TON network? The system message about CodeTON Round 9 said: <br> We are pleased to inform about your award for "CodeTON Round 9". The first 255 participants will receive prizes in USDT cryptocurrency in the TON network. Congratulations! Please provide your TON wallet address by link: https://codeforces.me/settings/wallets. Please be careful when filling in. The deadline is 23:59 December 8, 2024 (UTC). If you don't do this, then, unfortunately, we won't be able to transfer the prize to you. Join the TON, then register a wallet, follow one of these links: https://tonkeeper.com/ or https://wallet.ton.org/. <br> It's said that I would receive prizes in USDT, and recommended two wallets. The two wallets are the same as which mentioned in previous round messages. I was using ```https://wallet.ton.org/``` to receive prizes for previous round. But as far as I know this wallet is just for TON and doesn't support USDT. I have little knowledge in cryptocurrency. So here I kindly a...

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COderfocers Codeforces | In English По-русски pathetique | Logout HOMETOPCATALOGCONTESTSGYMPROBLEMSETGROUPSRATINGEDUAPICALENDARHELP → Pay attention Before contest Codeforces Global Round 26 3 days Register now » *has extra registration → pathetique pathetique User''s contest rating in Codeforces communityRating: 1448 User''s contribution into Codeforces communityContribution: -77 Settings Blog Favourites Teams Submissions Problemsetting Groups Talks Contests → Top rated # User Rating 1 tourist 3757 2 jiangly 3647 3 Benq 3581 4 orzdevinwang 3570 5 Geothermal 3569 5 cnnfls_csy 3569 7 Radewoosh 3509 8 ecnerwala 3486 9 jqdai0815 3474 10 gyh20 3447 Countries | Cities | Organizations View all → → Top contributors # User Contrib. 1 maomao90 171 2 awoo 164 3 adamant 163 4 TheScrasse 159 5 maroonrk 155 6 nor 154 7 -is-this-fft- 152 8 Petr 147 9 orz 145 10 pajenegod 144 View all → → Favourite groups # Name 1 X-Camp 402H 2022 Fall View all → → Fi...

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CodeTON Round 4 (Div. 1 + Div. 2) problems F and G – Video Editorial Hello, here's a video-editorial for problems F and G from the latest "CodeTON" contest with a little motivational speech in the beginning. https://www.youtube.com/watch?v=fJ_0M2DDEvw Thanks [user:RDDCCD,2023-04-01] and the TON Foundation for a cool contest!

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CodeTON Round 4 (Div. 1 + Div. 2) problems C–E – Video Editorial Hello, here's a video-editorial for problems B–E from today's contest. https://www.youtube.com/watch?v=c9A-fO6fPXQ Thanks [user:RDDCCD,2023-04-01] and the TON Foundation for a cool contest!

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