Hello 2024 Hello Codeforces, We are very glad to invite you to participate in [contest:1919], which will start on [contest_time:1919]. You will be given **8 problems** and **2.5 hours** to solve them. One of the problems will be divided into two subtasks. The round will be rated for everyone. There will be at most 2024 interactive problems, so please read the [guide for interactive problems](https://codeforces.me/blog/entry/45307) before the contest. All the problems are written and prepared by me. <spoiler summary="Spoiler"> The first tester tested on 10 October **2022**. </spoiler> We would like to give our sincere thanks to: - [user:errorgorn,2024-01-02] for his wonderful coordination! - [user:Alexdat2000,2024-01-02] for translating problem statements. - [user:dario2994,2024-01-02] for coming up with the solution to one of the problems. - [user:conqueror_of_tourist,2024-01-02], [user:iLoveIOI,2024-01-02], [user:Um_nik,2024-01-02], [user:oolimry,2024-01-02], [user:thenymphs...

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Goodbye 2022. Hello 2023! <img src="/predownloaded/f4/1f/f41ff0beb745fb2f84a55d9f2cc451273efc6267.jpg" style="width:300px; float:right; margin: 0 1em 1em 1em"/> Dear Santa Claus. Please make 2023 a happy year, not just that. Please, we all need this. Hello, 2023! And we have traditional gifts! #### <img src="https://assets.codeforces.com/images/wand.png"/> Change Handle Feature Hurry! Only until the 10th of January, you can change your handle (<b>but only once</b>)! Note that it will be possible to roll back the changes or change the handle again only _after a year_. Be careful what you wish for. You can change your handle to the new one which wasn't used before by anybody or which was used by you before. The links to a profile page with an old handle would automatically redirect to the actual profile. Again, this year if you took part in at least 10 rounds you can request a handle of an _inactive_ participant. It means that the participant should have a period of activity on Codeforces of...

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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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Good Bye 2022: 2023 is NEAR "It's been a long time since I came here, and I've really been through a lot." Koxia muses as she chatted idly with Mahiru. Now that the Winter Festival is approaching. Among the flash of fireworks, in the chimes of the New Year, what is waiting for them to encounter? Armed with girlish courage, they stepped onwards.  Hello Codeforces! We ([user:Nanako,2022-12-27], [user:m_99,2022-12-27], [user:huangxiaohua,2022-12-27], [user:SteamTurbine,2022-12-27], [user:triple__a,2022-12-27], [user:Nezzar,2022-12-27]) are very pleasured to invite you to take part in [contest:1770], which will take place in [contest_time:1770]! This round consists of **8 tasks** waiting for you to solve in **150 minutes**, and will be rated for everyone! On behalf of the author team, please allow me to express our sincere thanks to: * [user:errorgorn,2022-12-27], for useful guidance and brilliant advice during the coordinati...

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Codeforces Round #844 (Div. 1 + Div. 2) Hello! Welcome to the [contest:1782] that will start on [contest_time:1782]. It will be a combined rated round for both divisions and open to everyone. This round is a mirror of VK Cup 2022 Elimination — annual programming championship for Russian-speaking competitors organized by VK. VK Cup [started in 2012](https://codeforces.me/vkcup2012) and has grown to be a five-track competition in competitive programming, Mobile, ML, Go, and JavaScript. All the problems are authored and prepared by me. Thanks to [user:KAN,2023-01-13], [user:errorgorn,2023-01-13], [user:lperovskaya,2023-01-13], [user:dario2994,2023-01-15], [user:Monogon,2023-01-15], [user:Arpa,2023-01-15] for making this round better. You will be given 8 problems and 3 hours to solve them. **UPD**: [Editorial](https://codeforces.me/blog/entry/111783) Congratulations to the winners: 1. [user:orzdevinwang,2023-01-24] 2. [user:noimi,2023-01-24] 3. [user:Radewoosh,2023-01-24] 4. [user:gamegame,2023-01-24] ...

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Good Bye 2022, Hello 2023! <img src="/predownloaded/cf/40/cf40c72e68b2aee5005a91f39e1d3404d917617b.jpg" style="float:right; margin:0 1em 1em 1em;"/> Hello, Codeforces! The year 2022 is finally coming to an end. Let's be clear. It's been a terrible year. Tomorrow I will make a wish, and you can easily guess which one. I am writing these lines, and in a few minutes the Good Bye 2022 round will begin. And this inspires optimism and even pride in the community. Despite all these difficulties and troubles, we make rounds together and participate in them. Let's be grateful. And for this, let's say symbolic thanks to 2022 and a lot assistants: coordinators, problem writers, testers, participants and sponsors. We are many and we are together. Can I have a little more detail on the Codeforces team? Let me separately say thanks and words of admiration for the work of the coordinator of coordinators [user:KAN,2022-12-30] and the senior developer [user:geranazavr555,2022-12-30]. Both of you bring a lot to Cod...

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Codeforces Round #884 (Div. 1 + Div. 2) Hello, Codeforces! I invite everyone to participate in [contest:1844], which will start on [contest_time:1844]. The round is a combined round and will be rated for everyone. You will be given **8 problems** and **3 hours** to solve them. One of the problems is divided into two subtasks. The scoring distribution will be: $500$ &mdash; $1000$ &mdash; $1250$ &mdash; $1500$ &mdash; $2000$ &mdash; $(2000+1000)$ &mdash; $3500$ &mdash; $4000$ All problems are written and prepared by me. I would like to thank: * [user:irkstepanov,2023-07-10] for carefully coordinating the round. * [user:MikeMirzayanov,2023-07-10] for the wonderful Polygon and Codeforces platforms. * [user:4fecta,2023-07-10], [user:ak2006,2023-07-10], [user:amethyst0,2023-07-10], [user:AndreySergunin,2023-07-10], [user:BalintR,2023-07-10], [user:ChrisT,2023-07-10], [user:Div1D4Life,2023-07-10], [user:dorijanlendvaj,2023-07-10], [user:Dormi,2023-07-10], [user:errorgorn,2023-07-10], [user:Golovanov399,2023-07-...

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Hello 2023 Hello Codeforces! I am pleasured to invite you to take part in [contest:1779], which will take place in [contest_time:1779]! This round consists of $8$ tasks waiting for you to solve in $150$ minutes, and will be rated for everyone! As an author, please allow me to express my sincere thanks to: * [user:dario2994,2022-12-31], for being responsive, his amazing guidance, helping me prepare one of the problems and his truly wonderful coordination! * [user:KAN,2022-12-31], for rechecking and translating the round! * [user:wxhtzdy,2022-12-31], for proposing ~~rejected~~ tasks and discussing every problem with me * [user:giove,2022-12-31], for a problem idea which fits a gap. * [user:Um_nik,2022-12-31], [user:gamegame,2022-12-31], [user:JovanB,2022-12-31], [user:Marko,2022-12-31], [user:cip999,2022-12-31], [user:nweeks,2022-12-31], [user:NemanjaSo2005,2022-12-31], [user:Sofija06,2022-12-31], [user:Fikuss,2022-12-31], [user:badlad,2022-12-31], [user:Jovan08,2022-12-31], for p...

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Goodbye 2023. Hello 2024! <img src="/predownloaded/f4/1f/f41ff0beb745fb2f84a55d9f2cc451273efc6267.jpg" style="width:300px; float:right; margin: 0 1em 1em 1em"/> Dear Santa Claus. Please make 2024 a happy year, not just that. Please, we all need this. Hello, 2024! And we have traditional gifts! #### <img src="https://assets.codeforces.com/images/wand.png"/> Change Handle Feature Hurry! Only until the 10th of January, you can change your handle (<b>but only once</b>)! Note that it will be possible to roll back the changes or change the handle again only _after a year_. Be careful what you wish for. You can change your handle to the new one that wasn't used before by anybody or which was used by you before. The links to a profile page with an old handle would automatically redirect to the actual profile. Again, this year if you took part in at least 10 rounds you can request a handle of an _inactive_ participant. It means that the participant should have a period of activity on Codeforces of ...

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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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Codeforces Round 860 (Div. 2) Hello Codeforces! Невероятно рад пригласить вас на [contest:1798], который пройдёт в [contest_time:1798]. Раунд будет **рейтинговым для всех участников, чей рейтинг ниже 2100**. Участники с бóльшим рейтингом приглашены принять участие в раунде вне конкурса. Вам будет дано **6 задач** и **120 минут** на их решение. Все задачи раунда придуманы и подготовлены мной. Традиционный список благодарностей всем, кто принял участие в создании раунда: &#129332; [user:DishonoredRighteous,2023-03-19] за координирование раунда &#128030; [user:gyh20,2023-03-19] за чёрно-красное тестирование раунда &#128520; [user:feecIe6418,2023-03-19], [user:iakovlev.zakhar,2023-03-19], [user:Dart-Xeyter,2023-03-19], [user:Adam_GS,2023-03-19], [user:felys,2023-03-19], [user:golikovnik,2023-03-19], [user:Gary2005,2023-03-19] за красное тестирование раунда &#128043; [user:NemanjaSo2005,2023-03-19], [user:Alexdat2000,2023-03-19], [user:Kon567889,2023-03-19], [user:tem_shett,2023-03-19] за оранже...

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Codeforces Round 892 (Div. 2) #### <b><font size="6">Hello, Codeforces.</font></b> <img src="/predownloaded/14/cc/14cc4faf55cf00829bc2720470af02030a8165c2.jpg"> We are happy to invite you to [contest:1859], which will take place on [contest_time:1859]. All of the problems are original and were prepared by a collective of authors, consisting of [user:kristevalex,2023-08-09], [user:i_love_penguins,2023-08-09], [user:efimovpaul,2023-08-09] and me, [user:induk_v_tsiane,2023-08-09]. <b> This round will be rated for participants with a rating lower than 2100.</b> We would like to thank: - [user:Artyom123,2023-08-09] for coordinating the round. - [user:maomao90,2023-08-09], [user:Yuu,2023-08-09], [user:Qwerty1232,2023-08-09] and [user:Mangooste,2023-08-09] for GM testing. - [user:maks_matiupatenko,2023-08-09], [user:tiom4eg,2023-08-09], [user:ilyakrasnovv,2023-08-09], [user:sergeev.PRO,2023-08-09], [user:EJIC_B_KEDAX,2023-08-09], [user:Yar_sem,2023-08-09], [user:gmusya,2023-08-09], [user:zwezdinv,2023-08...

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Confession: I sent problem H to goodbye Going to be 100% honest here, I sent problem H to goodbye. I feel really bad to authors of Goodbye 2023 for ruining their round, it seems the round would have been better by just removing H. As much as the community is out here roasting [user:74TrAkToR,2023-12-31], I also had a part to play in this contest. I wish to be as transparent as I can here without saying any classified information (apologies to [user:KAN,2023-12-31] and [user:74TrAkToR,2023-12-31] if anything here shouldn't be disclosed). To give some context, here is what went down in goodbye round from my perspective: - 13 days before contest: KAN asks me if I can source a 1E for goodbye. I asked traktor to send me the testing gym so that I could gauge how hard the 1E should be. He told me he will send me after he translates the statements. (UPD: Note that the IMO 1986 problem was already removed before this stage which is why a new 1E was needed, I never saw this IMO problem) - 11 days before contest: traktor send it...

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Nebius Welcome Round (Div. 1 + Div. 2, rated, t-shirts!) Hello, Codeforces! [user:Zlobober,2023-03-09] and I are glad to invite you to compete in Nebius Welcome Round (Div. 1 + Div. 2) that will start on [contest_time:1804]. The round will be rated for everyone and will feature 8 problems that you will have 2 hours to solve. I feel really thrilled and excited about this round as this is the first time I put so much effort in a Codeforces contest since I quit being a round coordinator in December 2016 (wow, that was so long ago)! We conduct this round to have some fun and we also hope to find some great candidates to join Nebius team. Solving 5+ problems in our round will be a good result and will count as one of the coding interviews. Apart from that top 25 contestants and 25 random contestants placed 26-200 will receive a branded Nebius t-shirt! <img style="float: right; margin: 0 1em 0.5em 1em; width: 400px;" src="/predownloaded/40/37/403770e78d9c8962d0bc0c20a9e1c45d0e3c5df9.png"> Some information about Nebius. I have join...

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Codeforces Round 872 (Div. 1 & 2) Hello Codeforces! （你好，代码部队） We are glad to invite you to participate in [contest:1824] and [contest:1825] on [contest_time:1824]. **Please note the unusual start time.** This round is rated for **all the participants**. You will be given 5 problems (one of which is divided into two subtasks) and 2 hours to solve them in each division. Assume you are [user:YuezhengLing,2023-04-30], and in this round, your best friend [user:luotianyi,2023-04-23] will give you several problems to solve.  ([user:luotianyi,2023-04-23] is the left one and [user:yuezhengling,2023-04-30] is the right one) We would like to thank: 1. [user:RedLycoris,2023-04-22], [user:CrTsIr,2023-04-22], [user:Gyy_cj,2023-04-22], [user:SanweiTreap,2023-04-22] and [user:Gezhiyuan,2023-02-06] for writing the problems. 2. [user:Artyom123,2023-04-22] for coordinating the round. 3. [user:MikeMirzayanov,2023-05-06] for great Codeforces and Pol...

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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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1st Universal Cup Announcement Hello everyone, we are happy to announce that the 1st Universal Cup is started officially. Universal Cup is a non-profit organization dedicated to providing training for competitive programming teams. Our website is [https://ucup.ac/](https://ucup.ac/) (in English and Chinese). In recent years, Chinese problem-setter teams have created a great number of high-quality contests. We have reached an agreement with most of these setters, that they agree to provide contest materials to Universal Cup for hosting mirror contests before publishing the set in public. We believe that such an arrangement can provide good opportunities to teams who want to do better in the future competing. Every year, with the permission of the problem setter team and without involving copyright disputes, the Universal Cup will hold mirror contests for some undisclosed competition sets. It is expected to hold at least 10 contests a year. We will simulate the actual situation in the competition, using the ...

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April Fools Day Contest 2023 Hello, Codeforces! I, along with [user:AlperenT,2023-03-30], [user:Ari,2023-03-30], [user:BucketPotato,2023-03-30], [user:ScarletS,2023-03-30], and [user:ToxicPie9,2023-03-30], would like to invite everyone on Codeforces to the [contest:1812]! The 11th April Fools Day Contest will take place on [contest_time:1812]. This is a joke competition in which solving the problem is often easier than figuring out what the actual task is. Please note that the round is **unrated**. In this round you'll be given $n$ weird problems and 2 hours to solve them, where $7 \leq n \leq 12$. At most $\sqrt{n}$ of the problems will be [interactive](https://codeforces.me/blog/entry/45307). The contest will use ACM ICPC rules (no hacks, the standings are decided by the number of solved problems and penalty time earned on them). You can submit solutions in any language allowed by Codeforces, unless the problem says otherwise. To get an idea of what the contest will look like, you can check out the ...

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Editorial for Hello 2023 ## [problem:1779A] Author: [user:n0sk1ll,2022-12-27] <spoiler summary="Hint"> What happens when $\texttt{L}$ appears after some $\texttt{R}$ in the string? </spoiler> <spoiler summary="Solution"> Suppose that there exists an index $i$ such that $s_i = \texttt{R}$ and $s_{i+1} = \texttt{L}$. Lamp $i$ illuminates trophies $i+1,i+2,\ldots n$ and lamp $i+1$ illuminates $1,2,\ldots i$. We can conclude that all trophies are illuminated if $\texttt{L}$ appears right after some $\texttt{R}$. So, strings $\texttt{LLRRLL}, \texttt{LRLRLR}, \texttt{RRRLLL}, \ldots$ do not require any operations to be performed on them, since they represent configurations of lamps in which all trophies are already illuminated. Now, we consider the case when such $i$ does not exist and think about how we can use the operation **once**. Notice that if $\texttt{R}$ appears right after some $\texttt{L}$, an operation can be used to transform $\texttt{LR}$ into $\texttt{RL}$, and we have concluded before...

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Invitation to Codeforces Round 887 (Div. 1, Div. 2) Hello Codeforcers! ----------------------- I am pleased to invite y'all to participate in [contest:1852] and [contest:1853], which will start on [contest_time:1852]. In both divisions, you will be given $6$ problems and $2.5$ hours to solve them. The Div. $2 $ round will be rated for participants with rating below $1900$, while the Div. $1$ round will be rated for participants with ratings which are at least $1900$. This round was authored and prepared by [user:Benq,2023-06-02], [user:emorgan5289,2023-06-02], [user:omeganot,2023-06-02], [user:US3RN4M3,2023-07-17], me ([user:cry,2023-06-02]), [user:One,2023-07-17], [user:synths,2023-06-02], [user:buffering,2023-06-02], [user:ntarsis30,2023-06-02], and [user:ArielShehter,2023-06-02]. We want to thank the following people for their contributions: - Our amazing coordinator, [user:darkkcyan,2023-06-02], for the outstanding coordination despite the 12 hour time zone difference. - The rest of our problemsetting team for being...

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Codeforces Round 906 (Div. 1, Div. 2) Hello, Codeforces! [user:waaitg,2023-10-25], [user:Cocoly1990,2023-10-25] and I are glad to invite you to [contest:1889] and [contest:1890], which will take place on [contest_time:1889]. In both divisions, you will be given **6 problems** and **2 hours and 30 minutes** to solve them all. Note that one of the tasks is split into two subtasks. We would like to thank: - [user:TheScrasse,2023-10-25] for his brand new coordination. - [user:KAN,2023-10-25] for the great help with round preparation. - [user:Alexdat2000,2023-10-25] for Russian translation. - [user:errorgorn,2023-10-25] for his **1-year** coordination and [user:Monogon,2023-10-25] for his **2-year** coordination of one problem. - [user:waaitg,2023-10-25] for donating his Dead by Daylight time to prepare the problems. - [user:errorgorn,2023-10-25], [user:Kubic,2023-10-25], [user:zhangjianjuncd,2023-10-25], [user:doroc,2023-10-25], [user:DoverHi,2023-10-25], [user:alwyn,2023-10-25], [user:Yakumo_Ran,2023-10-25], [us...

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2nd Universal Cup Announcement Hello everyone, we are happy to announce that the 2nd Universal Cup has started officially. The Universal Cup is a non-profit organization dedicated to offering training resources for competitive programming teams. Our website is [https://ucup.ac/](https://ucup.ac/) (in English and Chinese). In the previous season, over 750 teams from more than 300 affiliations all over the world, registered and participated in a total of 22 stages, encompassing contests from Asia, Europe, and America. With the permission of contest setters and without involving copyright disputes, the Universal Cup will hold mirror contests for some undisclosed competition sets. It is expected to hold at least 20 contests in this season. We will simulate the actual situation in the competition, executing the board freeze in the last hour. At the same time, we will provide an overall rating board, which will help the team to make a reasonable assessment of itself. Over the past few weeks, the committee has...

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Codeforces Round #875 (Div. 1, Div. 2) Hello, Codeforces! Or, as we like to say in Romania: Sus Sus Sus, ca la [**Strehaia**](https://en.wikipedia.org/wiki/Strehaia) tată! I am glad to finally invite you to participate in [contest:1830] and [contest:1831], which will start on [contest_time:1830]. In both divisions, you will be given **6** problems and **2 hours and 30 minutes** to solve them. The problems were authored and prepared by [user:Andrei_ierdnA,2023-05-25], [user:Doru,2023-05-25], [user:Gheal,2023-05-25], [user:IacobTudor,2023-05-25], [user:LucaLucaM,2023-05-25], [user:RedstoneGamer22,2023-05-25], [user:SlavicG,2023-05-25], [user:Sochu,2023-05-25], [user:alecs,2023-05-25], [user:andrei_boaca,2023-05-25], [user:andrei_iorgulescu,2023-05-25], [user:lucaperju,2023-05-25], [user:valeriu,2023-05-25] and me ( <a class='rated-user user-gray' href='/profile/tibinyte'title='Cheater tibinyte'>tibinyte</a> ). I would like to thank: - [user:errorgorn,2023-05-25], for his wonderful coordination. - [user:irkst...

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Codeforces Round 899 (Div. 2) Hello, Codeforces! I am pleased to invite you to participate in [contest:1882], which will be held on [contest_time:1882]. All problems were written and prepared by me. You will be given **5 problems, and one of them is divided into two subtasks**. You will have **2 hours** to solve them. I would like to thank: - [user:irkstepanov,2023-09-21] for excellent coordination and Russian translation! - [user:Golovanov399,2023-09-21] for providing useful feedbacks. - [user:kizen,2023-09-21] for helping me much with one problem of the contest. - [user:ko_osaga,2023-09-21] for Nutella testing. - [user:leinad2,2023-09-21], [user:Numbering,2023-09-21], [user:qwerasdfzxcl,2023-09-21], [user:kizen,2023-09-21], [user:Golovanov399,2023-09-21] for Red testing. - [user:Kaling,2023-09-21], [user:Mingyu331,2023-09-21], [user:chaeyihwan,2023-09-21], [user:Kawaii2DIdolOfGSHS,2023-09-21], [user:azberjibiou,2023-09-21], [user:mjhmjh1104,2023-09-21], [user:DELTARUNE,2023-09-21], [...

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Polygon: AI-Powered Automatic Tips Hello, Codeforces! <i>For the new members of the community, I would like to remind you that Polygon (https://polygon.codeforces.com/) is a system developed and maintained by Codeforces for preparing programming problems. It is there that authors and coordinators develop all the problems for the rounds. Moreover, I believe a significant (large?) portion of the problems for other competitions is also developed there: various stages of ICPC, national competitions of different levels, educational problems for various courses, etc. <b>In 2023, more than 50000 problems were prepared in Polygon (only those for which a package was compiled are counted)!</b></i> Large language models are becoming an increasingly integral part of our lives, taking over routine and monotonous tasks. With their help, problems created in Polygon will now have fewer typos and incorrect language constructions. We have recently implemented three features in Polygon to ease routine tasks: * Translati...

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The 2023 ICPC World Finals Luxor <img src="/predownloaded/60/aa/60aa49ecdb6a668539163c4d7d797ac6f1bb43b3.jpg" align="right" style="height: 350px; margin: 10px 20px 20px;" alt="text"/> Hello Codeforces! The 2023 ICPC World Finals Luxor will begin on [April 18, 2024 at 10:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=2023+ICPC+World+Finals+Luxor&iso=20240418T12&p1=4626&ah=5). 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 [user:ecnerwala,2024-04-17], [user:SecondThread,2024-04-17], [user:Egor,2024-04-17], 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 gr...

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Polygon Updates (August — September 2023) Hello, Codeforces! I, [user:ChurakovaAlexandra,2023-10-13], and [user:medvezhonokok,2023-10-13] are students of ITMO, and since this August, we started our internship at Codeforces. We are delighted that now we have the opportunity not only to write academic code but to do something that competitive programming enthusiasts from all over the world use. Currently, we are working on minor improvements to Polygon &mdash; a system for preparing problems. Later, as we gain more experience and delve into the technologies, we will also start working on Codeforces. A big thank you to our mentors [user:geranazavr555,2023-10-13] and [user:MikeMirzayanov,2023-10-13], who are always there to help and support. Here's a list of the main improvements to Polygon that we've made (sometimes with significant help from our mentors) over these two months. [cut]<br/> ###### 1. Automatic translation of solutions from one programming language to another. On the 'Solutions' page, a 'Tra...

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Codeforces Round #850 Hello! Welcome to [contest:1785] and [contest:1786] that will start on [contest_time:1785]. Both rounds will be rated. This round is a mirror of VK Cup 2022 Final — annual programming championship for Russian-speaking competitors organized by VK. VK Cup [started in 2012](https://codeforces.me/vkcup2012) and has grown to be a five-track competition in competitive programming, Mobile, ML, Go, and JavaScript. All the problems of Div. 1 round are authored and prepared by me, while [user:KAN,2023-02-05] authored and prepared two problems for Div. 2. Thanks to [user:errorgorn,2023-02-03], [user:irkstepanov,2023-02-03], [user:qwerty787788,2023-02-05], [user:Merkurev,2023-02-05], [user:IgorI,2023-02-05], [user:PavelKunyavskiy,2023-02-05], [user:izban,2023-02-05], [user:Alexdat2000,2023-02-05], [user:I_Remember_Olya_ashmelev,2023-02-05], [user:Akulyat,2023-02-05], [user:mike_live,2023-02-05], [user:Ekler,2023-02-05], [user:Kalashnikov,2023-02-05] for making this round better. You w...

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Codeforces Round #912 (Div. 2) Γεια σου (Hello), Codeforces once again! [user:Adam_GS,2023-11-25] and I are glad to invite you to participate in [Codeforces Round #912 (Div. 2)](https://codeforces.me/contest/1903) which will take place on [contest_time:1903]. **Note the unusual start time of the round**. As usual, **this round will be rated for participants with rating lower than 2100.** Problems were created and prepared by [user:Adam_GS,2023-11-25] and me. We tried to make them interesting, with short and clear statements. We hope that you will enjoy them! I would like to thank: - [user:ScarletS,2023-11-25] for amazing coordination of this round. - [user:Adam_GS,2023-11-25] for joining as an author after testing the contest. - [user:fishy15,2023-11-25], [user:Andreasyan,2023-11-25], [user:phattd,2023-11-25], [user:Murinh0,2023-11-25], [user:irkstepanov,2023-11-25], [user:wuhudsm,2023-11-25], [user:Ari,2023-11-25], [user:satyam343,2023-11-25], [user:Qualified,2023-11-25], [user:nyaruhod...

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Codeforces Round #905 (Div. 1, Div. 2, Div. 3) Hello, Codeforces! We are happy to invite you to our experimental round for three divisions, which will take place at [contest_time:1887]. <b>Please note the non-standard start time for the round</b>. Each division will have 5-7 tasks. The round will be held according to the Codeforces rules and will be rated for all three divisions. A few changes regarding the ratings of participants in this competition: <ul style="list-style-type:square"> <li>In Div.3 the rating of participants is less than 1600. </li> <li>In the Div.2 ranking, participants range from 1600 to 2099. </li> <li>In Div.1 the rating of participants is no less than 2100.</li> <li><b>Please note</b> that after [contest:1884] the rating will not be recalculated until the end of this competition. </li> </ul> Let us note that two team Olympiads will be held in parallel on this day and the rounds are based on their tasks: <ul style="list-style-type:square"> <li> XXI Moscow Team Olympiad, high school stud...

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Codeforces Round #851 (Div. 2) Hello Codeforces and welcome back to another div2 round. [user:YeongTree,2023-02-06] and I are excited to invite everyone to participate in [contest:1788], which will be held on [contest_time:1788]. This round is rated for the participants with ratings strictly lower than **2100**. You will be given **6 problems** and **2 hours** to solve them. All the problems are authored and prepared by [user:YeongTree,2023-02-06] and me. We would like to thank - [user:Arpa,2023-02-06] for excellent coordination and help with prepration. - [user:Alexdat2000,2023-02-06] for Russian translation. - [user:tlsdydaud1,2023-02-06], [user:hypergraph_coloring,2023-02-06], [user:Kawaii2DIdolOfGSHS,2023-02-06], [user:nlog,2023-02-06], [user:Ryute,2023-02-06], [user:TheQueenOfHatred,2023-02-06], [user:hanbyeol_,2023-02-06], [user:Physics07,2023-02-06], [user:jjang36524,2023-02-06], [user:OctaneC8H18,2023-02-06], [user:ahgus89,2023-02-06], [user:DELTARUNE,2023-02-06], [user:Go3,2023-02-06], [user:a...

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Educational Codeforces Round 142 [рейтинговый для Div. 2] Привет, Codeforces! В [contest_time:1792] состоится [contest:1792]. Продолжается серия образовательных раундов в рамках инициативы [Harbour.Space University](https://harbour.space/)! Подробности о сотрудничестве [Harbour.Space University](https://harbour.space/) и Codeforces можно прочитать <a href="http://codeforces.me/blog/entry/51208">в посте</a>. 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 [...

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Codeforces Round 864 (Div. 2) Hello, Codeforces! [user:AC-Automation,2023-04-05] and I [user:rui_er,2023-04-05] are glad to invite you to participate in [contest:1797], which will be held on [contest_time:1797]. **Please note the unusual start time.** This round is rated for the participants with ratings strictly lower than **2100**. You will be given **6 problems** and **2 hours** to solve them. All the problems are prepared by [user:AC-Automation,2023-04-05] and me. We would like to thank: - [user:darkkcyan,2023-04-05] for a perfect coordination and help with the problem preparation. - [user:AC-Automation,2023-04-05] for providing some <s>rejected</s> problems and helping me a lot in preparation. - [user:zplqwq,2023-04-05] for polishing English statements and editorials. - [user:Alexdat2000,2023-04-05] for the Russian translations. - [user:N_z__,2023-04-05], [user:HQJ2007,2023-04-05], [user:2_3_3,2023-04-05], [user:ShmilyTY,2023-04-05], [user:tlsdydaud1,2023-04-05], [user:fishy15,2023-04-05], [use...

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The 1st Universal Cup. Stage 13: Iberia Hello Codeforces! The 13th Stage of the 1st Universal Cup is coming. It will be held from April 22nd to 23rd. This contest was first used in the Petrozavodsk Programming Camp Winter 2023, and also appeared in the 2023 ICPC Training Camp powered by Huawei and the Hello Muscat 2023 Bootcamp. If you participated in any of those, you should not participate in this stage of the Universal Cup. All the problems were authored and prepared by [user:998batrr,2023-04-21], [user:244mhq,2023-04-21], [user:353cerega,2023-04-21] (Harbour.Space [P+P+P](https://codeforces.me/team/102621), Barcelona, Spain) and [user:Um_nik,2023-04-21] (Lisbon, Portugal). We want to thank the Universal Cup Committee for staying true to the spirit of 5h/3person/1pc contests and for providing the opportunity to share our contest with a wider audience. As usual, we have three time windows for participating. You can participate in the contest in the following three time windows: [Time Window 1: April 22nd 13...

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Codeforces Round #861 (Div. 2) <a href="https://ibb.co/hB6SF5F"><img src="https://i.ibb.co/48qHRyR/350-20230320195909.png" alt="350-20230320195909" border="0"></a> Hello, Codeforces! I am very glad to invite you to the [Codeforces Round #861 (Div. 2)](https://codeforces.me/contest/1808), which will take place in [contest_time:1808]. <b>This round will be rated for the participants with rating lower than 2100.</b> My sincere thanks to: - [user:KAN,2023-03-26] и [user:aleks5d,2023-03-26] for the great coordination of this round! - [user:Wind_Eagle,2023-03-26], [user:BaluconisTima,2023-03-26], [user:kartel,2023-03-26], [user:gepardo,2023-03-26] and [user:244mhq,2023-03-26] for the tasks ideas, and also [user:BaluconisTima,2023-03-26], [user:244mhq,2023-03-26], [user:VEGAnn,2023-03-26], [user:Vladik,2023-03-26] and [user:andrew,2023-03-26] for preparing the tasks. - [user:vilcheuski,2023-03-26] and [user:programmer228,2023-03-26] the rest of the author team, without whom this round would not have happ...

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Codeforces Command Lines (2023-10-06) Hello, Codeforces! We've compiled a list of command lines that Codeforces uses to compile and run solutions in various languages and compilers. It is up-to-date as of today (2023-10-06), and we will make efforts to keep it current in the future, but this is not guaranteed. [cut]<br/> Language/Tool |Bitness|Compilation/Build Command |Run Command | |----------------------------------|-------|--------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------| |GNU GCC C11 5.1.0 |32 |gcc -std=c11 -static -DONLINE_JUDGE -fno-asm -lm -s -Wl,--stac...

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[RANT] Warning to other coordinators about Wuhudsm Hi again, it is me. I want to preface this blog by saying that I am totally aware that it is not good netiquette to screenshot private messages and publish them publicly. But honestly, I can't care anymore now. Below is an unorganized rant. Sorry, I'm too pissed to write the things below concisely. And here: I'm pinging him: [user:wuhudsm,2024-07-21]. In an ideal world, I could probably just tell him privately to stop doing it. But I already did. So I think I need to write this blog to either stop him from doing this again or just soft-ban him from authoring more rounds by telling everyone about it. Let me just preface this blog with a fact of coordination -- it is very possible that problems from contest A will be used in contest B even after testers from contest A have seen those problems. So there are indeed (many) testers who could possibly be affected by this. Some examples of this happening (where I was involved): - Contest problems based on on-site contests were quit...

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COMPFEST 15 Preliminary Online Mirror (Unrated, ICPC Rules, Teams Preferred) <img alt="logo" src="/predownloaded/54/ec/54ec8a2a974eb225636db378f5470e039144d49b.png" style="float: right;height: 100.0px;margin: 10.0px;max-width: 100.0%;max-height: 100.0%;"> Hello, **Codeforces**! &#x1f60d;&#x1f60d; We are happy to invite you to participate in [COMPFEST 15 Preliminary Online Mirror (Unrated, ICPC Rules, Teams Preferred)](https://codeforces.me/contests/1866) on <a class="contest-time" contestid=1866></a>. COMPFEST is a national **ICPC-style contest** for university students in Indonesia. The problems are written and prepared by [user:ArvinCiu,2023-08-30], [user:asteriskzie,2023-08-30], [user:CyberSleeper,2023-08-30], [user:Edbert.H,2023-08-30], [user:FreeJinG,2023-08-30], [user:gansixeneh,2023-08-30], [user:KokiCoder,2023-08-30], [user:nandonathaniel,2023-08-30], and [user:Pyqe,2023-08-30]. We would also like to thank: - [user:KAN,2023-08-30] for helping to host the mirror round; - [user:AMnu,2023-08-30], ([user:KerakTelor,2023-08-30], [user:Owmic...

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[Suggestion] Faster statement loading at the start of the contest #### Hello codeforces, The past two rounds (Goodbye 2022, Hello 2023) had quite a lot of participants, which is great, but comes with the downside of a very long loading time for the website at the beginning of the contest, reaching **5 minutes** in "Hello 2023" for me personally. This kind of delay is annoying in general, but especially during the critical first few minutes of the contest where wasting time on problem A is costly. Now, the obvious solution would be adding additional resources to the server during peak times, but there's only one<strong style="color:red;">*</strong> big burst of requests and submissions and it cools down pretty fast, so in any case a method to move some of the load on the server to a different time would be very helpful. My suggestion is publishing the problemset in advance, even 30 minutes before the start, *encrypted*. Then, at the start of the contest the encryption key would be broadcasted to everyone, letting them decrypt the relatively ...

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Codeforces Round #873 (Div. 1 & 2) Hello, Codeforces! [user:thenymphsofdelphi,2023-05-09], [user:lanhf,2023-05-09], and I are delighted to invite you to take part in [contest:1827] and [contest:1828] which are going to take place at [contest_time:1827]. Participants with a rating lower than 1900 will participate in Division $2$, while participants with a rating of at least 1900 will participate in Division $1$. In both divisions, you will be given **2 hours** to solve **6 problems** (one of which is divided into two subtasks), all of which were authored and prepared by me, [user:lanhf,2023-05-09], and [user:thenymphsofdelphi,2023-05-09]. We would like to thank the following people who made our round possible: - [user:74TrAkToR,2023-05-09] for his great coordination and help with the problems' preparation during the last 4 months. - [user:khuepr123,2023-05-09] for doing nothing but being the mascot. - [user:A05,2023-05-09], [user:Kawaii,2023-05-09], [user:SeehEternity,2023-05-09], [user:yanglake,2023-05-09], ...

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Codeforces Round #881 (Div. 3) Hello, Codeforces! On [contest_time:1843] [contest:1843] will start. You will be offered 7 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**. You will be given **7 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](https://codeforces.me/blog/entry/59228) 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 partic...

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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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Codeforces Round 911 (Div. 2) Hello, Codeforces! [user:Riblji_Keksic,2023-11-25] and I are glad to invite you to [contest:1900], which will start on [contest_time:1900]. You will be given **6** problems and **2** hours to solve them. The round will be rated for participants of Division 2 with a rating lower than **2100**. Division 1 participants can participate unofficially. All problems are invented and prepared by [user:Riblji_Keksic,2023-11-25] and me. Special thanks go to [user:n0sk1ll,2023-11-25] and [user:TimDee,2023-11-25] for their great work during the testing process of the round. And of course, I would love to thank the people who made this round possible: - [user:pashka,2023-11-25] for his great coordination of the round! - [user:IgorI,2023-11-25] for helping host the round! - [user:Alexdat2000,2023-11-25] for helping translate the round! - [user:prvocislo,2023-11-25], [user:wxhtzdy,2022-06-02], [user:valeriu,2023-11-25], [user:satyam343,2023-11-25], [user:n0sk1ll,2023-11-25...

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Codeforces Round #845 (Div. 2) and ByteRace 2023 Hello, Codeforces! NJACK &mdash; the Computer Science Club of IIT Patna is excited to invite you to **ByteRace 2023** &mdash; [contest:1777] under **Celesta** &mdash; the annual Techno-Management Fest of IIT Patna. The contest will take place on [contest_time:1777]. **This round will be rated for participants with rating lower than 2100.**  Many thanks to all the people who made this round possible: - The problems were authored and prepared by me, [user:quantau,2023-01-19], [user:mayankfrost,2023-01-19], [user:ShivanshJ,2023-01-19], [user:Crocuta,2023-01-19] and [user:AwakeAnay,2023-01-19]. - [user:irkstepanov,2023-01-19] and [user:KAN,2023-01-19] for coordinating the round! - [user:jenishmonpara,2023-01-19], [user:100gods,2023-01-19] and [user:V_S_M,2023-01-19] for their guidance throughout the process. - VIP testers: [user:YashPant,2023-01-19] and [user:Newtech66,2023-01-19] <3 - Shoutout to [us...

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Codeforces Round #866 (Div.1, Div.2, based on Lipetsk Team Olympiad) Hello, Codeforces! This Saturday VIII Lipetsk Team Olympiad, a competition for high school students from all over the country, will be held in Lipetsk. Maybe you participated in previous Codeforces rounds based on our problems (rounds [643](https://codeforces.me/contest/1355) and [791](https://codeforces.me/contest/1679)). The round will start at [contest_time:1819] and will last for 2 hours. **Please notice the unusual time.** Each division will have 6 problems. The round will be held according to the Codeforces rules and will be rated for both divisions. Problems were proposed and prepared by [user:Um_nik,2023-04-12], [user:DishonoredRighteous,2023-04-12], [user:FairyWinx,2023-04-12], [user:golikovnik,2023-04-12], [user:teraqqq,2023-04-12], [user:grphil,2023-04-12], [user:Kon567889,2023-04-12], [user:TeaTime,2023-04-14], [user:Tikhon228,2023-04-12] and [user:dshindov,2023-04-12]. I would like to thank [user:Artyom123,2023-04-12] for great round coordination and our test...

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Invitation to NUS CS3233 Final Team Contest 2023 Mirror <img alt="logo" src="/predownloaded/7a/2d/7a2da3823042e763e0d15d6571ba0bcb38139f90.png" style="float: right;height: 100.0px;margin: 10.0px;max-width: 100.0%;max-height: 100.0%;"> Hello, Codeforces community! We are happy to invite you to participate in [National University of Singapore (NUS) CS3233 Final Team Contest 2023 Mirror](https://codeforces.me/contestInvitation/3d3b392eb92ff65022128f4e22462d5eaff55a25) on [Monday, April 10, 2023, at 09:35 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?day=10&month=4&year=2023&hour=12&min=35&sec=0&p1=166). CS3233 is a course offered by NUS to prepare students in competitive problem solving. The contest is unofficial and will be held in Codeforces Gym. Standard ICPC rules **(Unrated, ICPC Rules, Teams Preferred)** apply. **The contest is unrated**. **Note the unusual starting time**. The problems are written and prepared by [user:user202729_,2023-04-08], [user:rama_pang,2023-04-08], and [user:pooty,2023-04-08]. We wo...

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Goodbye... top 1 contributor :( It's about time... 6 months have passed since Hello 2024 and the [halving](https://codeforces.me/blog/entry/76361?#comment-608729) is taking place. It is about time I retire from my top 1 contribution spot :( I want to take this opportunity to thank the community for being so generous with your upvotes for my Hello 2024 round. Thank you for letting me have this achievement of reaching the top contributor spot that not many people will get to experience. Regarding this, I hope that people will be more generous with their upvotes for other rounds as well. A big part of why Hello 2024 received so many upvotes is that Goodbye 2023 was not a great round. If a round went smoothly with no serious issues, why not upvote the round? This will encourage the problem-setters and motivate them to create more rounds in the future. In return for the community's support, I am considering writing some educational blogs. Let me know what type of blog you want to see from me in the comments. I am c...

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Codeforces Round 895 (Div. 3) Hello Codeforces! [contest:1872] will start at [contest_time:1872]. You will be offered 7 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**. You will be given **7 problems** and **2 hours and 15 minutes** to solve them. Note that the **penalty** for wrong submission in this round is **10 minutes**. [Remember](https://codeforces.me/blog/entry/59228), 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 t...

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Codeforces Round 980 (Div.1, Div. 2) Hello, Codeforces! We're glad to invite you to take part in Codeforces Round 980 (Div.1, Div. 2), which will start on [contest_time:2023]. **Note the unusual time of the round.** Each division will have 6 problems and 2 hours to solve them. The round will be held according to the Codeforces rules and will be rated for both divisions. The problems were authored and prepared by [user:Mangooste,2024-10-18], [user:Tikhon228,2024-10-18], [user:adepteXiao,2024-10-18], [user:Artyom123,2024-10-18], [user:sevlll777,2024-10-18], [user:yunetive29,2024-10-18], [user:glebustim,2024-10-18], [user:Endagorion,2024-10-18], [user:isaf27,2024-10-20] guided by [user:Ormlis,2024-10-18] and Helen Andreeva. The round is based on XXII Moscow Team Olympiad, high school students competition based in Moscow that is an elimination contest for All-Russian Team Olympiad. Also thanks to the authors of the Olympiad whose problems were not included in the round : [user:vaaven,2024-10-18], [user:TeaTime,2024-10-1...

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Codeforces Round 914 (Div. 2) ### **Note the unusual time of the round.** Hello Codeforces! [user:lunchbox,2023-12-07], [user:Apple_Method,2023-12-07], and I are pleased to invite you to participate in [contest:1904] on [contest_time:1904]. You will be given 2 hours to solve 6 problems (and one subtask). **The round will be rated for participants of Division 2 with a rating lower than 2100**. We promise the statements will be clear and concise, suitable for [user:AdamantChicken2,2023-12-07] to read *wink wink*. --- Also, we would like to thank: - [user:errorgorn,2023-12-07] for the epic coordination. - [user:alexdat2000,2023-10-03] for the Russian translations. - [user:MikeMirzayanov,2023-12-07] for the amazing Codeforces and Polygon platforms (and finally taking Polygon off beta). - <a href="https://codeforces.me/profile/enderbeat"><strong><font color="#a0a">[VIP] EnDeRBeaT</font></strong></a> for testing and statement assistance. - <a href="https://codeforces.me/profile/omeganot"><stron...

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The 1st Universal Cup. Stage 4: Ukraine Hello everyone! The 4th Stage of the 1st Universal Cup: Ukraine, will be held on Feb 18th, 2023. The contest is based on 1/8 and 1/4 Ukrainian stages of SEERC 2023, plus some extra problems. Please, don't participate, if you have seen these problems. This contest also serves as Day 1 in [Osijek Competitive Programming Camp 2023](https://codeforces.me/blog/entry/110945) on February 18, 2023. Author of all problems: [user:antontrygubO_o,2023-02-14]. I hope you like the problems. You can participate in the contest in the following three time windows: * Feb 18th 13:00 &mdash; 18:00 (UTC +8) * Feb 18th 19:00 &mdash; 24:00 (UTC +8) * Feb 19th 02:00 &mdash; 07:00 (UTC +8) Please note that you can see two scoreboards in DOMjudge. The 'Local Scoreboard' shows the standings ONLY IN THE CURRENT TIME WINDOW. And the 'Combined Scoreboard' shows all participants, including the onsite participants, and the cup participants in the previous time windows. Contest link: https://domj...

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CerealCodes Summer 2023 Programming Contest <center> Hello Codeforcers :3 </center> ================= **UPD 1: Opening ceremony on [Friday 7PM EST](https://www.timeanddate.com/worldclock/fixedtime.html?iso=20230811T190000&p1=179). Join our [Discord server](https://discord.gg/qve3dBA8Ek) for more information** **UPD 2: Contest has started! You may start your window anytime over the next 2 days. Join our [Discord server](https://discord.gg/qve3dBA8Ek) to ask clarifications for any problems. Good luck!** From the authors behind [contest:1852] and [contest:1853], CerealCodes is excited to announce our Summer 2023 Programming Contest! This contest will be held on August $13 - 15$ th with a customizable time-frame window. The time limit for novice is $3$ hours while intermediate and advanced are allowed $3.5$ hours. All of the contest information, including exact start and end times, can be found [here](https://www.cerealcodes.org/contestinfo). The competition has three divisions: Novice (USACO Bronze-Silver or Div....

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April Fools Day Contest 2024 Hello, <s>April Fools lovers</s> Codeforces! We, [user:AlperenT,2024-03-26], [user:flamestorm,2024-03-26], [user:toxicpie9,2024-03-26], and [user:willy108,2024-03-26], would like to invite everyone on Codeforces to [contest:1952]! The 12th April Fools Day Contest will take place on [contest_time:1952]. This is a joke competition in which solving the problem is often easier than figuring out what the actual task is. In this round, you will be given $n$ cool bugaboos where $-1 \le n \le \textbf{[REDACTED]}$ and **2** hours to solve them. The contest will use extended ICPC rules (no hacks, the standings are decided by the number of solved problems and penalty time earned on them). You can submit solutions in any language allowed by Codeforces, unless the problem says otherwise. Please note that the round is **unrated** and that the penalty for a **wrong submission** is **10** minutes. To get an idea of what the contest will look like, you can check out the contests of the pas...

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Codeforces Round #843 (Div. 2) <a href="https://ibb.co/whxngNB"><img src="https://i.ibb.co/1GwCQf7/38-20230104210158.png" alt="38-20230104210158" border="0"></a> Hello, Codeforces! I am very glad to invite you to the [Codeforces Round #843 (Div. 2)](https://codeforces.me/contest/1775), which will take place in [contest_time:1775]. <b>This round will be rated for the participants with rating lower than 2100.</b> My sincere thanks to: - [user:KAN,2023-01-08] и [user:aleks5d,2023-01-08] for the great coordination of this round! - [user:Wind_Eagle,2023-01-08], [user:BaluconisTima,2023-01-08], [user:kartel,2023-01-08] и [user:aleks5d,2023-01-08] for the tasks ideas, and also [user:Wind_Eagle,2023-01-08], [user:BaluconisTima,2023-01-08], [user:kartel,2023-01-08], [user:VEGAnn,2023-01-08] и [user:Vladik,2023-01-08] for preparing the tasks. - [user:andrew,2023-01-08], [user:gepardo,2023-01-08], [user:244mhq,2023-01-08], [user:vilcheuski,2023-01-08] the rest of the author team, without whom this round woul...

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Codeforces Round #876 (Div. 2) Hello, Codeforces! I invite you to participate in [contest:1839], which will be held on [contest_time:1839]. The round will be rated for participants with rating lower than 2100. Participants with higher rating can participate in round unofficially. You will be given 5 problems and 2 hours to solve them. I recommend you to read all problems. One of the problems will be interactive, so please read [guide for interactive problems](https://codeforces.me/blog/entry/45307) before the contest. All problems are authored by me. I would like to thank: - [user:Renatyss,2023-06-01] for helping with preparation and discussing the problems. - [user:IgorI,2023-06-01] for great round coordination. - [user:bashkort,2023-06-01], [user:Allvik06,2023-06-01], [user:Ormlis,2023-06-01], [user:satyam343,2023-06-01], [user:maomao90,2023-06-01], [user:Dominater069,2023-06-01], [user:Yuu,2023-06-01], [user:Kirill020708,2023-06-01], [user:asafiul,2023-06-01], [user:iliya_mon,2023-06-01], ...

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The 2nd Universal Cup. Stage 11: Nanjing Hello! I'm happy to announce The 2nd Universal Cup. Stage 11: Nanjing, which will be held on November 25th, 2023. This contest is an official ICPC Regional Contest &mdash; The 2023 ICPC Asia Nanjing Regional Contest. The contest is prepared by the [SUA Programming Contest Problem Setter Team](https://sua.ac/), which was the fourth time for us to prepare the Nanjing Regional Contest. Due to the covid pandemic, the previous three Nanjing regionals were held online. As the pandemic has come to an end, we can finally gather in NUAA to participate in this wonderful contest. <div class="row"> <img src="/predownloaded/5c/18/5c188f4d780927880fd5d129119baea901acaabf.jpeg" style="height: 262.0px;max-width: 100.0%;max-height: 100.0%;"> <img src="/predownloaded/3e/09/3e095e729a6804b2a0bf171a7b06551f25c82368.jpg" style="height: 262.0px;max-width: 100.0%;max-height: 100.0%;"> </div> <div class="row"> <img src="/predownloaded/54/2f/542f1b72c1b4d6225be048a9ad31aac153ce7ad5.jpg" style...

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Codeforces Round #848 (Div. 2) Hello, Codeforces! [user:adnan_toky,2023-01-23] and I are super thrilled to invite everyone to participate in [contest:1778], which will be held on [contest_time:1778]. This round is rated for the participants with ratings strictly **lower than 2100**. You will be given **6 problems** and **2 hours** to solve them. All the problems are authored and prepared by [user:adnan_toky,2023-01-25] and me. To get the 6 problems approved, we needed to propose 12 problems in total <a href="https://emoji.gg/emoji/6390-sneaky-wink-catto"><img src="https://cdn3.emoji.gg/emojis/6390-sneaky-wink-catto.png" width="16px" height="16px" alt="sneaky_wink_catto"></a>. **UPD:** Score distribution: $500-1000-1250-1750-2250-2750$ We would like to thank: - [user:darkkcyan,2022-02-12] for incredible coordination and help with the problem preparation - [user:Alexdat2000,2022-07-16] for the Russian translations and precious help regarding the statements and limits - [user:KAN,2023-01-30] for upgrad...

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Educational Codeforces Round 141 [рейтинговый для Div. 2] Привет, Codeforces! В [contest_time:1783] состоится [contest:1783]. Продолжается серия образовательных раундов в рамках инициативы [Harbour.Space University](https://harbour.space/)! Подробности о сотрудничестве [Harbour.Space University](https://harbour.space/) и Codeforces можно прочитать <a href="http://codeforces.me/blog/entry/51208">в посте</a>. 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 [...

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Codeforces Round 896 (Div. 1, Div. 2) Hello, Codeforces! & Happy Chinese Teachers' Day! We (OICon Team) are so excited to invite you to take part in OICon Round 1 ([contest:1868] and [contest:1869]) which will start on [contest_time:1868]. You will be given 6 problems and 2.5 hours to solve them in both divisions. * **Please notice the unusual starting time!** * One of the problems has two versions but their statement are not exactly the same, which means that you **can't** pass the easy version using the code of the hard version. However, you can only make hacks when you pass both versions. * There will be $0$ interactive problem in each division so you needn't read the [guide for interactive problems](https://codeforces.me/blog/entry/45307). * Score distribution: * Div. 1: $500-(500+750)-1000-1750-2500-3000$ * Div. 2: $500-750-1250-(1250+1500)-2500-3250$ The problems were authored and prepared by [user:Error_Yuan,2023-09-03], [user:duck_pear,2023-09-03], [user:programpiggy,2023-09-03] and me. We...

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Codeforces Round #862 (Div. 2) Hello, everyone at Codeforces.com! In this round, I ([user:Alexdat2000,2023-04-01]) and two of my friends &mdash; [user:FairyWinx,2023-04-01] and [user:Sevlll777,2022-06-03] &mdash; prepared **6 problems** for you (one of which is divided into two subtasks), and you will have **2 hours** to solve them. Everyone is welcome to follow the link: [contest:1805] at [contest_time:1805]. **This round will be rated for all participants with a rating of strictly less than 2100.** And now a few acknowledgements: - Thanks to [**<font color="#ff0000">[Coordinator] pashka</font>**](https://codeforces.me/profile/pashka) for coordinating and helping with testers - Special thanks to [**<font color="#ff0000">[G.O.A.T.] Mangooste</font>**](https://codeforces.me/profile/Mangooste) for discussing tasks and testing - Thanks to all the testers: [**<font color="#000000">[MVP</font><font color="#ff0000">++</font><font color="#000000">] Ormlis</font>**](https://codeforces.me/profile/Ormlis...

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Every Technique and Algorithm I Used to Become Grandmaster Hi everyone, I became grandmaster today so I decided to go down memory lane and review every problem I have ever done in a CodeForces contest to look back and see every technique and algorithm I had to use to become a grandmaster. I am not sure how useful this is, I mostly think it's fun to look at all the old solutions I wrote and how different it was from how I write code now. The main takeaway is that, as many people have said before, you don't need to know or memorize a bunch of advanced algorithms to become grandmaster. As you will see, there are many problems where I just used "ad hoc reasoning," meaning there's not a standard technique I used to solve the problem and you just need to make some clever mathematical observations to solve the problem. Also, there are many popular algorithms that I have never needed in a CodeForces contest despite being a grandmaster: - Sparse tables, Fenwick trees, and segment trees - String algos, like rolling hashes, Knuth-Morris-Pratt, suffix...

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ICPC 2023 Online Challenge powered by Huawei <img src="/predownloaded/60/ed/60eddb18a54159e57dd1ffc836857f58420039bf.jpg" align="right" style="height: 280px;" alt="text"/> #### Hello, Codeforces! From the ICPC 2023 World Finals, we are happy to bring you an exciting online event: **The ICPC 2023 Online Challenge powered by Huawei**，which will start on November 20, 2023 15:00 UTC (UTC+8) 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.** #### The ICPC 2023 Online Challenge powered by Huawei: **Start:** [November 20, 2023 15:00 (UTC+8)](https://www.timeanddate.com/worldclock/fixedtime.html?day=20&month=11&year=2023&hour=10&min=0&sec=0&p1=166) **Finish:** [December 4, 2023 15:00 (UTC+8)](https://www.timeanddate.com/worldclock/fixedtime.html?day=04&month=12&year=2023&hour=10&min=0&sec=0&p1=166) **We hope you'll enjoy this ...

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The Brazilian IOI 2023 Team was selected and it is stacked Hello codeforces! Because of weird scheduling issues, the brazilian TST is normally made at december of the year before IOI, different from the rest of the countries. So, today was the last day of TST and after 4 days of contests we have our team settled:  From left to right, we have: - Leonardo Valente Nascimento ([user:definitelynotmee,2022-12-10]) - Rafael Nascimento Soares ([user:Deepesson,2022-12-10]) - Arthur Lobo Leite Lopes ([user:LoboLobo,2022-12-10]) - Pedro Suyama Leston Rey ([user:pedroslrey,2022-12-10]) In case youre curious, here is a screenshot of the scoreboard so you can see how everyone went.  We were quite comfortably above 5th place in the end, but i had a headache on the first day so i wasn't even top 4 on it. The problems were also really good, as they typically are (even though i can't say the same...

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Codeforces Round 886 (Div. 4) Hello Codeforces! [user:mesanu,2023-07-20], [user:flamestorm,2023-07-20] and I are very excited to invite you to [contest:1850]! It starts on [contest_time:1850]. 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_ wil...

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Invitation to TOKI Indonesian NOI Open Contest 2023 Hello Codeforces community, We are excited to invite you to **TOKI Indonesian NOI Open Contest 2023** — an online mirror contest for the Indonesian National Olympiad in Informatics. This national olympiad is one of the stages required for our students to qualify to represent Indonesia in the International Olympiad in Informatics (IOI). You may have seen our past open olympiads ([2015](https://codeforces.me/blog/entry/17924), [2016](https://codeforces.me/blog/entry/44892), [2017](https://codeforces.me/blog/entry/53037), [2018](https://codeforces.me/blog/entry/60263), [2019](https://codeforces.me/blog/entry/67967), [2020](https://codeforces.me/blog/entry/83514), [2021](https://codeforces.me/blog/entry/96689), [2022](https://codeforces.me/blog/entry/107378)), and you can check our past problems [here](https://tlx.toki.id/problems/problemsets?archive=osn). The contest is similar to IOI: 2 competition days (+ 1 trial session), each consisting of 3 IOI-style (partial, subtasks)...

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Codeforces Round #849 (Div. 4) Hello Codeforces! [user:flamestorm,2022-08-28], [user:SlavicG,2023-02-01], [user:MikeMirzayanov,2022-07-11] and I want to invite you to [contest: 1791]. It starts on [contest_time: 1791]. 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...

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TeamsCode Spring 2023 Contest Hello Codeforces! [TeamsCode](http://teamscode.org) is excited to announce the [TeamsCode Spring 2023 Virtual Programming Contest](https://www.teamscode.org/contests/spring-2023)! It will take place on [April 2nd, 2023 at 9:45 AM PST](https://www.timeanddate.com/worldclock/fixedtime.html?msg=TeamsCode+Spring+2023+Contest&iso=20230402T0945&p1=1239&ah=3). **Teams of up to 4 members will have 3 hours to solve around 10 problems.** There are two divisions: Novice and Advanced, so no matter what skill level you are, there is a place for you. The guest speaker events will feature **Dr. Subho Majumdar**, a technical leader in applied trustworthy machine learning who believes in a community-centric approach to data-driven decision-making, and **Dr. Jane Bae**, an Assistant Professor of Aerospace at the Graduate Aerospace Laboratories at Caltech. She received her Ph.D. in Computational and Mathematical Engineering from Stanford University in 2018. She was a postdoctoral fellow in the Grad...

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Codeforces Round #909 (Div. 3) Hello, Codeforces! ☀️☀️☀️ We are glad to invite you to our second [Div. 3](https://codeforces.me/contest/1899) round, which will take place on [contest_time:1899]. **The round will be rated for all participants with rating less than 1600.** You will be given 7 tasks and 2 hours 15 minutes to solve it. The tasks were prepared by [user:zwezdinv,2023-11-15], [user:meowcneil,2023-11-15], [user:EJIC_B_KEDAX,2023-11-15], [user:Sokol080808,2023-11-15] and [user:molney,2023-11-15]. [Remember](https://codeforces.me/blog/entry/59228), that only _trusted Div. 3 participants_ will be included in official standings. To qualify as trusted participant you need: 1. Participate in at least five rounds (and solve at least one problem in each of them) 2. Do not to have a point 1900 or greater in the rating We would like to thank: - [user:MikeMirzayanov,2023-11-15] for Polygon and Codeforces - Coordinators [user:Vladosiya,2023-11-15] and [user:Gornak40,2023-11-15] for excellent ...

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Codeforces Round #903 (Div. 3) Hello! [contest:1881] will start at [contest_time:1881]. 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**. You will be given **7 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](https://codeforces.me/blog/entry/59228) 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...

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Codeforces Round #888 (Div. 3) Hello! [contest:1851] will start at [contest_time:1851]. 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**. You will be given **7 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](https://codeforces.me/blog/entry/59228) 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...

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TeamsCode Summer 2023 Contest Hello Codeforces! [TeamsCode](http://teamscode.org) is excited to announce the [TeamsCode Summer 2023 Virtual Programming Contest](https://www.teamscode.org/contests/summer-2023)! It will take place on [August 12th, 2023 at 9:15 AM PST](https://www.timeanddate.com/worldclock/fixedtime.html?msg=TeamsCode+Summer+2023+Contest&iso=20230812T0915&p1=283). **Teams of up to 4 members will have 3 hours to solve around 10 problems.** There are two divisions: Novice and Advanced, so no matter what skill level you are, there is a place for you. The guest speaker events will feature **Michael Plunkett**, an experienced software engineer of 10+ years and a second-year graduate student at the Harris School of Public Policy at the University of Chicago. The schedule is shown below: <spoiler summary="Schedule">  </spoiler> Our prize pool for winners of the novice and advanced divisions is over $5,000! **Only pre-col...

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Codeforces Round #897 (Div. 2) Hello, Codeforces! &#129327; [user:green_gold_dog,2023-09-11], [user:ace5,2023-09-09], [user:bashkort,2023-09-09] and I [user:salyg1n,2023-09-09] are pleased to invite you to participate in [Codeforces Round 897 (Div. 2)](https://codeforces.me/contest/1867 ), which will take place on [Monday, September 11, 2023 in 17:35](https://www.timeanddate.com/worldclock/fixedtime.html?day=11&month=9&year=2023&hour=17&min=35&sec=0&p1=166). This round will be **rated** for participants whose **rating is below 2100**. You will be given 6 tasks and 2 hours to solve them. We recommend reading all the tasks. **Interactive tasks may occur in the round**, so we suggest reading this [post] (https://codeforces.me/blog/entry/45307 ). We want to thank: - [user:Aleks5d,2023-09-09] for coordinating the round and improving one of the tasks. &#129299; - [user:Allvik06,2023-09-09], [user:Nutella3000,2023-09-09], [user:arbuzick,2023-09-09], [user:alegsandyr,2023-09-09], [user:maomao90,2023-09-0...

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XVIII Open Olympiad in Informatics (2023-2024) Hello, Codeforces! We have started the qualification contest of the **Open Olympiad in Informatics**! The Open Olympiad in Informatics is one of the most prestigious and challenging olympiads for school students in Russia. Every year, the most experienced students from Russia and other countries participate in the final of the olympiad. Starting this year, the results of the Open Olympiad will also be taken into account for the selection of participants for the Russian national team in informatics at various international olympiads. The tasks for the olympiad are prepared by the Moscow Olympiad Scientific Committee that you may know by Moscow Team Olympiad, Moscow Olympiad for Young Students and Metropolises Olympiad (rounds [327](https://codeforces.me/blog/entry/21185), [342](https://codeforces.me/blog/entry/23309), [345](https://codeforces.me/blog/entry/43615), [376](https://codeforces.me/blog/entry/47769), [401](https://codeforces.me/blog/entry/50613), [433](https://codeforc...

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Codeforces blocking my account for a fake cheating accuse Requested to publish from [user:Basilhijaz,2023-10-09]: " Hello, I am [user:Basilhijaz,2023-10-09]. I participated in lots of Codeforces rounds and the last one I did was [contest:1879]. Unfortunately, I was trying to login to my account today and got the message "User is disabled by administrators". I checked my email and it looks like I was accused of cheating in that specific round. Apparently my Submission on Problem B [submission:224888371] is so close to [user:LetsPractice,2023-10-09]'s Submission [submission:224901176]. This problem we both got accused of copying from each other is B in an Educational round which means solutions can get actually really close and if you notice the solutions are so short which increases the probability of matching. Previous Accuses of Cheating Attempts (Problem, My Submission, Similar Submission/s)(problem classification): - ([problem:1462D], [submission:101301240], [submission:101299306]) (D div3). - ([problem:1670A], [submi...

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[GYM] Al-Baath Collegiate Programming Contest 2023 Hello, Codeforces! I am happy to invite you to participate in [contest:104447] that was held at the Al-Baath University [contest_time:104447]. The problems were authored and prepared by [user:Prince_Kassad,2023-05-14], [user:Blade-Master,2023-06-26], [user:KiFaH_HeLaL,2023-06-26], [user:Geo_Ghaffar,2023-06-26], [user:Basharo,2023-06-26], [user:molhaam1,2023-06-26], [user:somar_mh,2023-06-26], [user:Tinky-Winky,2023-06-26], and me. I would like to give our sincere thanks to: - [user:Nihad_Nabelsi,2023-06-26], [user:aminsh,2023-06-26] for yellow testing. - [user:mahersefo,2023-06-26], [user:OverSimpIified,2023-06-26] for purple testing. - [user:Raito_Yagami,2023-06-26], [user:NeroZein,2023-06-26], [user:edogawa_something,2023-06-26], [user:Besher_Zaiback,2023-06-26], [user:FzArK,2023-06-26], [user:kaislash.,2023-06-26], [user:Ayham_Dabah,2023-06-26] for blue testing. - [user:Mohammad_soleman,2023-06-26] for cyan testing. - [user:Rama_i_am,2023-06-26], [user:dina_s...

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Codeforces Round 913 (Div. 3) Hello! [contest:1907] will start at [contest_time:1907]. 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**. 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](https://codeforces.me/blog/entry/59228) 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 thi...

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Teams Qualified for Africa and Arab Collegiate Programming Championship — ACPC 2023 (+teens) Hello, Codeforces community! I would like to congratulate all the teams that have qualified for ACPC2023. I'm thrilled to meet and compete with all of you in this year's competition. Since we're approximately a month away from the event, I believe it's a good idea to get to know the participating teams and assess their current levels. It's also a great idea to add them as friends to compete against them virtually in gyms. If you qualified for this year's competition Please comment the following information and I'll update the blog as soon as possible. ( I will make a separate table for teens) - Country - University(!teens) - Team name - Team handles(separated by spaces) I will add the team rating about a week before the competition as there might be some new grandmasters by then :) Finally, "Welcome to ACPC" And good luck to all the teams! ACPC Teams ------------------ | **#** | **Country** | **University** | **Team name** | **...

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Hello Muscat 2023 **<font color="#625bb7">Hello, Codeforces!</font>** We are pleased to announce the second “Hello Muscat 2023” ICPC programming bootcamp, the continuation of the “Hello” bootcamp series, organised by **<font color="#625bb7">Harbour.Space University</font>**, in collaboration with **<font color="#625bb7">PhazeRo</font>**, **<font color="#625bb7">Gutech</font>**, **<font color="#625bb7">UK Oman Digital Club</font>**, **<font color="#625bb7">Leagues of Code</font>**, **<font color="#625bb7">Gutech CS Club</font>** and **<font color="#625bb7">Codeforces</font>**! We are inviting all of you to join us from **<font color="#625bb7">March 8th to March 16th, 2023 in Muscat, Oman for an intense 8 days of programming</font>**! It is not only a great opportunity to train but also a chance to discover a new amazing country. There are many reasons why you must visit Oman at least once in your life, from its great people to its natural beauty and surrounding peace. **March is an especially grea...

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April Fools Day Contest 2026 Hello, Codefoolers! We, [user:AlperenT,2026-03-29], [user:Ari,2026-03-29], [user:ToxicPie9,2026-03-29], [user:flamestorm,2026-03-29], [user:prvocislo,2026-03-29], [user:temporary1,2026-03-29], and [user:willy108,2026-03-29] would like to invite everyone on Codeforces to [contest:2214]! The 14th April Fools Day Contest will take place on [contest_time:2214]. This is a joke competition in which solving the problem is often easier than figuring out what the actual task is. In this round, you will be given $n$ problems where $n$ is the number of different AI models I used today and **2** hours to solve them. The contest will use extended ICPC rules (no hacks, the standings are decided by the number of solved problems and penalty time earned on them). You can submit solutions in any language allowed by Codeforces, unless the problem says otherwise. There will be at least one non-interactive problem. In case you do not care about those problems, [here](https://codeforces.me/blog/e...

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Codeforces Round #874 (Div. 3) Hello! [contest:1833] will start at [contest_time:1833]. 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**. 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](https://codeforces.me/blog/entry/59228) 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 thi...

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Codeforces Round #855 (Div. 3) Hello! [contest:1800] will start at [contest_time:1800]. 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**. 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](https://codeforces.me/blog/entry/59228) 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 thi...

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[CONTEST OVER] MIT Informatics Tournament 2024 Spring Invitational **Update 2**: The Qualification Round has **officially concluded**! A huge thank you to our contestants for joining us and supporting this new initiative! Congratulations to the top 16 finalists who are advancing to the finals round (along with many more as we continue to confirm people's availability)! 1. [user:Rewinding,2024-04-24] 2. [user:ksun48,2024-04-24] 3. [user:Petr,2024-04-24] 4. [user:Geothermal,2024-04-24] 5. [user:mango_lassi,2024-04-24] 6. [user:hank55663,2024-04-24] 7. [user:ecnerwala,2024-04-24] 8. [user:MiFaFaOvO,2024-04-24] 9. [user:Kevin114514,2024-04-30] 10. [user:A_G,2024-04-30] 11. [user:Adam_GS,2024-04-24] 12. [user:Tourist,2024-04-24] 13. [user:FlowerOfSorrow,2024-04-24] 14. Matthew Allan 15. [user:uwu,2024-04-24] 16. [user:TLE,2024-04-24] At this time, the scoreboard has been finalized, and you can upsolve our problems / watch our video tutorials with the following links: - Finalized Scoreboard: [https://mitit.org/Contest/ViewScoreboar...

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The 2nd Universal Cup. Stage 23: Shanghai (ICPC Asia EC Finals 2023) Hello everyone! We are thrilled to invite you to **The 2nd Universal Cup, Stage 23: Shanghai**, taking place on February 17th, 2024. This stage is based on The 2023 ICPC Asia East Continent Final Contest, which is the last contest in the Asia EC Region in this season. 280 official teams participated in the onsite contest competed for the last WF slots of the season.  I would like to thank all task writers for their efforts on preparing the contest. They are [user:dXqwq,2024-02-16], [user:jqdai0815,2024-02-16], [user:Kubic,2024-02-16], [user:littlelittlehorse,2024-02-16], [user:MagicalFlower,2024-02-16], [user:Qingyu,2024-02-16], [user:QuietBeautifulThoughts,2024-02-16], [user:unputdownable,2024-02-16], and [user:xyz2606,2024-02-16]. Also a big thank you to all the people who tested the contest and gave their valuable advice: [user:__ZMF__,2024-02-16], [user:antontrygubO_o,2024-02-16], [user:chenjb,2...

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JOI Spring Camp 2023 Online Contest Hello, everyone! [Japanese Olympiad in Informatics (JOI) Spring Camp 2023](https://contests.ioi-jp.org/joi-sp-2023/index-en.html) will be held from March 19 to March 22. There are **4 days** in this contest. * Day 1: [March 19, 02:00 GMT — March 19, 24:00 GMT](https://www.timeanddate.com/worldclock/fixedtime.html?msg=Japanese+Olympiad+in+Informatics+%28JOI%29+Spring+Camp+2023+Day1&iso=20230319T02&p1=1440&ah=22) * Day 2: [March 20, 02:00 GMT — March 20, 24:00 GMT](https://www.timeanddate.com/worldclock/fixedtime.html?msg=Japanese+Olympiad+in+Informatics+%28JOI%29+Spring+Camp+2023+Day2&iso=20230320T02&p1=1440&ah=22) * Day 3: [March 21, 02:00 GMT — March 21, 24:00 GMT](https://www.timeanddate.com/worldclock/fixedtime.html?msg=Japanese+Olympiad+in+Informatics+%28JOI%29+Spring+Camp+2023+Day3&iso=20230321T02&p1=1440&ah=22) * Day 4: [March 22, 02:00 GMT — March 22, 24:00 GMT](https://www.timeanddate.com/worldclock/fixedtime.html?msg=Japanese+Olympiad+in+Informatics+%28JOI%29+Spring+C...

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Codeforces Round 859 (Div. 4) Hello Codeforces! [user:mesanu,2023-03-18], [user:flamestorm,2023-03-18] and I are very excited to invite you to [contest:1807]! It starts on [contest_time:1807]. 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_ wil...

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Codeforces Round 901 (Div. 1, Div. 2) Hello, Codeforces! I'm pleased to invite you to [contest:1874] and [contest:1875]. It starts on [contest_time:1874]. It also means, the National Day of China arrives during the round. Wish you a nice vacation! &#127881;&#127881;&#127881; For both divisions, you will have **3 hours** to solve **7 problems**. I would like to thank: - [user:errorgorn,2023-09-27] for his wonderful coordination. - [user:Alexdat2000,2023-09-27] for Russian translation and [user:Vladosiya,2023-09-30] for helping us with Russian clarifications. - [user:GeZhiyuan,2023-09-27] for providing all the problems and "a few" rejected problems. - [user:znstz2018,2023-09-27] and [user:SanweiTreap,2023-09-27] for helping me prepare the problems. - [user:Um_nik,2023-09-27], [user:wangziji,2023-09-27], [user:Heltion,2023-09-27], [user:Kevin114514,2023-09-27] and [user:flowerletter,2023-09-27] for Legendary Grandmaster Testing. - [user:sjcsjcsjc,2023-09-27], [user:He_Ren,2023-09-27], [user:Gary,20...

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Codeforces Round #910 (Div. 2) Hello, Codeforces! [user:ELDRVD,2023-11-15] and I are glad to invite you to [contest:1898], which will start on [contest_time:1898]. You will be given **6** problems and **2** hours to solve them. The round will be rated for participants of Division 2 with a rating lower than 2100. Division 1 participants can participate unofficially. All problems are invented and prepared by [user:ELDRVD,2023-11-15] and me. Special thanks go to [user:Sofija06,2023-11-15] and [user:NemanjaSo2005,2023-12-04], our two most dedicated testers. We would also like to honor: - [user:prvocislo,2023-11-15], [user:wuhudsm,2023-11-15], [user:Marckess,2023-11-15], [user:MateoCV,2023-11-15], [user:Wibo,2023-11-15], [user:curly_braces,2023-11-15], [user:LucaLucaM,2023-11-15], [user:null0124,2023-11-15], [user:OAleksa,2023-11-15], [user:AlphaMale06,2023-11-15], [user:FireFrog418,2023-11-15], and [user:sahaun,2023-11-15] for testing this round and providing valuable feedback! - [user:IgorI,2023-11-15] f...

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Codeforces Round #940 and CodeCraft-23 (Div. 2) ## Hello Codeforces! We're glad to invite everyone to participate in [contest:1957], which will start on [contest_time:1957]. The contest will be rated for all the Div. 2 participants (Rating < 2100). The [Programming Club at IIIT-H](https://iiit-programming-club.github.io/) 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 <s>2 hours</s> 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! - [user:ScarletS,2023-12-01] and [user:KAN,2024-04-18] for their wonderful coordination. - [user:Alexdat2000,2022-07-17] for translating the problem statements to Russian. - [user:akcube,2024-04-18], [user:fangahawk,2024-04-18], [user:Geng...

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JOI 2022/2023 Final Round Online Contest Hello, everyone! [The 22nd Japanese Olympiad in Informatics (JOI 2022/2023) Final Round](https://contests.ioi-jp.org/joi-ho-2023/index-en.html) will be held from [Sunday, February 12th, 10:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=JOI+2022/2023+Final+Round&iso=20230212T10&p1=1440) to [Monday, February 13th, 10:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=JOI+2022/2023+Final+Round&iso=20230213T10&p1=1440). The contest information is as follows: * Contest duration: **4 hours** (You can choose start time freely in 24-hour window) * Number of tasks: **5 tasks** * Max score for each task: **100 points** * Style: **IOI-Style** (There may be some partial scores) * Problem Statement: **Japanese & English** Note that since the contest ends at [Monday, February 13th, 10:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=JOI+2022/2023+Final+Round&iso=20230213T10&p1=1440), if you start the contest after [Monday, February 13th...

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JOI Open Contest 2023 Hello everyone! [JOI Open Contest 2023](https://contests.ioi-jp.org/open-2023/index.html) will be held from [Saturday, August 5, 04:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=JOI+Open+Contest+2023&iso=20230805T04&p1=1440) to [Sunday, August 6, 04:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=JOI+Open+Contest+2023&iso=20230806T04&p1=1440). You can start any time and the duration is basically 5 hours. Note that the duration becomes shorter if you start after [Saturday, August 5, 23:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=JOI+Open+Contest+2023&iso=20230805T23&p1=1440), i.e. less than 5 hours before the contest ends. There will be **3 tasks**, and the maximum score for each task is **100 points**. Since this is an IOI-style contest, **there may be some subtasks**. Each submitted source program must be written **only in C++**. Problem statements will be provided both in Japanese and in English. You can find more deta...

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JOI 2023/2024 Final Round Online Contest Hello, everyone! [The 23nd Japanese Olympiad in Informatics (JOI 2023/2024) Final Round](https://contests.ioi-jp.org/joi-ho-2024/index-en.html) will be held from [Sunday, February 04th, 10:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=JOI+2023/2024+Final+Round&iso=20240204T10&p1=1440) to [Monday, February 05th, 10:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=JOI+2023/2024+Final+Round&iso=20240205T10&p1=1440). The contest information is as follows: * Contest duration: **4 hours** (You can choose start time freely in 24-hour window) * Number of tasks: **5 tasks** * Max score for each task: **100 points** * Style: **IOI-Style** (There may be some partial scores) * Problem Statement: **Japanese & English** Note that since the contest ends at [Monday, February 05th, 10:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=JOI+2023/2024+Final+Round&iso=20240205T10&p1=1440), if you start the contest after [Monday, February 05th...

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April Fools Day Contest 2025 Hello, Codefoolers! We, [user:AlperenT,2025-03-28], [user:flamestorm,2025-03-28], [user:prvocislo,2025-03-29], [user:temporary1,2025-03-28], [user:Toxicpie9,2025-03-28], and [user:-1e11,2025-03-28], would like to invite everyone on Codeforces to [contest:2095]! The 13th April Fools Day Contest will take place on [contest_time:2095]. This is a joke competition in which solving the problem is often easier than figuring out what the actual task is. In this round, you will be given $n$ problems where $\sum\limits_{x=1}^{\infty} \frac{1}{x^n}$ converges and **2** hours to solve them. The contest will use extended ICPC rules (no hacks, the standings are decided by the number of solved problems and penalty time earned on them). You can submit solutions in any language allowed by Codeforces, unless the problem says otherwise. Please note that the round is **unrated** and that the penalty for a **wrong submission** is **10** minutes. To get an idea of what the contest will look lik...

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The 2nd Universal Cup. Stage 13: Shenyang Hello! I'm happy to announce The 2nd Universal Cup. Stage 13: Shenyang, which will be held on December 9th, 2023. This contest is an official ICPC Regional Contest — The 2023 ICPC Asia Shenyang Regional Contest. It is the 9th consecutive year that Northeastern University has hosted the ICPC Asia Shenyang Regional Contest. Great thanks to the host school for preparing the Regional, and the hard work done by all staff and volunteers for this contest. <img src="/predownloaded/24/83/2483ceaf571339751e32ed2e5401c5d08bd6db18.jpg" width="35%" height="35%" /> <img src="/predownloaded/e3/fb/e3fb46fa993b6b46dadb89ee7b0aac495abb5d29.jpg" width="27%" height="27%" /> <img src="/predownloaded/00/8c/008c2d13555c6d9b32427762cc02559356f52e08.jpg" width="35%" height="35%" /> The authors for preparing the contests: [user:Sulfox,2023-12-06], [user:quailty,2023-12-06], [user:lzr_010506,2023-12-06], [user:calabash_boy,2023-12-06], [user:Gromah,2023-12-06]. The testers for their valuable advice: ...

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Codeforces Round #867 (Div.3) Hello! [contest:1822] will start at [contest_time:1822]. 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**. 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](https://codeforces.me/blog/entry/59228) 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 thi...

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[CONTEST OVER] MIT Informatics Tournament (M(IT)^2) 2024 **UPDATE 3**: There was a typo in the registration link that led to the pre-registration form. If you filled that out, please fill out our actual [registration form](https://mitit.org/Registration). Note that with the contest **within 24 hours**, we cannot guarantee we review all applications in time. Please submit ASAP if you would like to be considered. Apologies for the inconvenience. **UPDATE 2: The contest is in less than a week! Note that we changed the venue from the MIT Media Lab to [Huntington Hall (10-250)](https://whereis.mit.edu/print_window.html?zoom=16&lat=42.359674020000014&lng=-71.09201372&maptype=mit&q=10-250&open=object-10). There will be thousands of dollars in cash prizes and also exclusive merchandise!** The schedule for contest day is below. We are excited to see everyone! - **8 AM &mdash; 9 AM:** Contestants check-in + breakfast - **9 AM &mdash; 10 AM:** Opening Ceremony + Last minute team formation - **10 AM &mdash; 10:30 AM:** Buffer time as teams ar...

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Codeforces Round 916 (Div. 3) Hello, Codeforces! On [contest_time:1914] the [contest:1914] will start. 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, during the round, solutions will be judged on preliminary tests, and after the round it will be a 12-hour phase of open hacks. You will be given **2 hours and 15 minutes** to solve **6-8 problems**. The penalty for a wrong submission is equal to **10 minutes**. [We remind you](https://codeforces.me/blog/entry/59228) that only _the trusted participants of the third division_ will be included in the official standings table. As it is written on the blog which you can access by this link, this is a compulsory measure for combating unsporting behavior. To qualify as _a tru...

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5th place curse in Turkish Team Selection Contest and my goodbye Hello, I want to talk about an ongoing curse in Turkey. I am the most recent victim of that curse at it's 9th year. Let's start with the beginning. #### 2015-2016 Curse starts with [user:ErdemKirez,2023-05-10] taking 5th place in 2015. After that year, he tried his best and was in the team in 2016. But because of some reasons Turkey team wasn't able to participate IOI 2016. After that, the curse has started. You can look at this [blog](https://codeforces.me/blog/entry/54007) for details. #### 2017 I don't know who was at 5th place that year. But probably curse was active. #### 2018-2019 In 2018, [user:TahsinEnesKuru,2023-05-10] got 5th place. 3/4 of that team was at their last year so he had a high chance of being in the team at 2019. But he didn't know, he was already cursed. He missed the team with a difference of 3/700. He also has a [blog](https://codeforces.me/blog/entry/66811) about it. #### 2020 At that year, [user:ExpertHunter,2023-05-10] got 5th place. He was at hi...

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Codeforces Round #847 (Div. 3) Hello! [contest:1790] will start at [contest_time:1790]. 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**. 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](https://codeforces.me/blog/entry/59228) 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 thi...

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The 1st Universal Cup. Stage 7: Zaporizhzhia Hello everyone! The 7th Stage of the 1st Universal Cup: Zaporizhzhia, will be held on March 11th, 2023. The contest is based on the Day 2: Oleksandr Kulkov Contest 3 from the [Osijek Competitive Programming Camp 2023](https://codeforces.me/blog/entry/113438). Please, don't participate if you have seen these problems. Authors of the problems: [user:adamant,2023-03-07], [user:fedimser,2023-03-07], I would also like to thank [user:-is-this-fft-,2023-03-07] for the help with the preparation of the contest. We hope you will like the problems! You can participate in the contest in the following three time windows: * Mar 11th 13:00 &mdash; 18:00 (UTC +8) * Mar 11th 19:00 &mdash; 24:00 (UTC +8) * Mar 12th 02:00 &mdash; 07:00 (UTC +8) Please note that you can see two scoreboards in DOMjudge. The 'Local Scoreboard' shows the standings ONLY IN THE CURRENT TIME WINDOW. And the 'Combined Scoreboard' shows all participants, including the onsite participants, and the cup partici...

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2nd Universal Cup. Stage 5: Northern Hello, Codeforces! I'm pleased to announce the 5th stage of the 2nd Universal Cup. It will be held from October 14th to October 15th. The contest was prepared for you by the SPbSU LOUD Enough team ([user:tranquility,2023-10-11], [user:nikgaevoy,2023-10-11] and [user:Kaban-5,2023-10-11]), a bronze medalist of ICPC World Finals in Dhaka. We (the authors) would also like to thank [user:Gassa,2023-10-11], [user:snarknews,2023-10-11] and [user:SoshkinRoman,2023-10-11] for some useful feedback and technical assistance. And, of course, we would like to thank the organizers of Universal Cup for letting us hold our contest as a stage of Universal Cup and share it with a wider audience. This contest was first used in the Petrozavodsk Programming Camp Winter 2023, and also appeared in the 2023 ICPC Training Camp powered by Huawei and the Hello Muscat 2023 Bootcamp. **If you participated in any of those, please refrain from participating in this stage of the Universal Cup**. It is importa...

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Codeforces Global Rounds 2022: Final Results (GR19-GR24) Hello, Codeforces. It's time to take stock of last year. Shall we begin? And we are happy to sum up the results of the last season of Global Rounds. We announce the results! We remind you that the global rounds are a joint initiative of XTX and Codeforces. We hold 6 such rounds per year. All of them are open to both divisions. At each such round, 50 brand T-shirts were handed out, and we are happy to give T-shirts to all problem authors. The prizes for the 6-round series are: - In each round top-100 participants get points according to the [table](https://pastebin.com/QT5sXEaT). - 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. [cut] The final standings after six rounds (sorted by total points in four best-placed rounds): | Place | Contestant | = | GR 19 | GR 20 | GR 21 | GR 22 | GR 23 | GR 24| |--|--|--|--|...

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Codeforces Round 907 (Div. 2) Hello, Codeforces! [user:max0000561,2023-10-26], [user:a.nasretdinov,2023-10-26] and I are glad to invite you to our [contest:1891], which will be held on [contest_time:1891]. <b>The round will be rated for all the participants with rating strictly less than 2100</b>. On behalf of our team, I want to thank: <ul style="list-style-type:square"> <li>Coordinator [user:74TrAkToR,2023-10-26] for invaluable help in preparing the round.</li> <li>Testers [user:maomao90,2023-10-26], [user:LeoPro,2023-10-26], [user:SomethingNew,2023-10-26], [user:maks_matiupatenko,2023-10-26], [user:max0000561,2023-10-26], [user:yaroslav_n,2023-10-26], [user:glebustim,2023-10-26], [user:aone_A1,2023-10-26], [user:Murinh0,2023-10-26], [user:Topperoo,2023-10-26], [user:Alarick,2023-10-26], [user:priyanshu.p,2023-10-26], [user:Greg908,2023-10-26], [user:buffering,2023-10-26], [user:ventilator13,2023-10-26], [user:medved,2023-10-26], [user:zwezdinv,2023-10-26], [user:Rodionno,2023-10-26] for high-quality t...

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Codeforces Round 898 (Div. 4) Hello Codeforces! [user:flamestorm,2023-09-20], [user:MikeMirzayanov,2022-07-11] and I want to invite you to [contest: 1873]. It starts on [contest_time: 1873]. 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_ wi...

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Codeforces Round #900 (Div. 3) Hello, Codeforces! [user:ognjentesic,2023-09-23], [user:wxhtzdy,2023-09-23], [user:OAleksa,2023-09-23], [user:AndrewPav,2023-09-23], [user:acanikolic73,2023-09-23] and I are glad to invite you to the [contest:1878]. It starts on [contest_time:1878] You will be given **7 problems** and **2 hours and 15 minutes** to solve them. Note that the **penalty** for the wrong submission in this round is **10 minutes**. Also note that there will be a **12 hour open hacking phase** after the round. [Remember](https://codeforces.me/blog/entry/59228), 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...

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Hello Muscat 2023 **<font color="#625bb7">Hello, Codeforces!</font>** It is the last call to register for the 2nd “Hello Muscat 2023” ICPC programming bootcamp, the continuation of the “Hello” bootcamp series, organised by **<font color="#625bb7">Harbour.Space University</font>**, in collaboration with **<font color="#625bb7">PhazeRo</font>**, **<font color="#625bb7">Gutech</font>**, **<font color="#625bb7">UK Oman Digital Club</font>**, **<font color="#625bb7">Leagues of Code</font>**, **<font color="#625bb7">Gutech CS Club</font>** and **<font color="#625bb7">Codeforces</font>**! We are inviting all of you to join us from **<font color="#625bb7">March 8th to March 16th, 2023 in Muscat, Oman for an intense 8 days of programming</font>**! It is not only a great opportunity to train but also a chance to discover a new amazing country. **March is an especially great time to visit Oman if you want to enjoy nice beach weather &mdash; don’t miss it!** As always, we can’t wait to see you there to l...

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Educational Codeforces Round 150 [Rated for Div. 2] Hello Codeforces! On [contest_time:1841] [contest:1841] will start. Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="http://mirror.codeforces.com/blog/entry/51208">blog post</a>. 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 [user:adedalic,2023-06-11] Dalabaev, Ivan [user:BledDest,2023-06-11] Androsov, Maksim [user:Neon,2023-06-11] Mesche...

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IOI 2023 Country Standings Hello everyone! Similar to [last year](https://codeforces.me/blog/entry/105957), these are the country standings for IOI 2023 based on the sum of scores of all contestants. Check the spoiler at the bottom for the complete list. <table style="width:100%"> <tr> <th>Rank</th> <th>Team</th> <th>Score</th> </tr> <tr> <td>1</td><td>CHN</td><td>1997.5</td></tr> <tr> <td>2</td><td>USA</td><td>1624.5</td></tr> <tr> <td>3</td><td>JPN</td><td>1574</td></tr> <tr> <td>4</td><td>IOI_2</td><td>1463.5</td></tr> <tr> <td>5</td><td>TWN</td><td>1296</td></tr> <tr> <td>6</td><td>KOR</td><td>1218.5</td></tr> <tr> <td>7</td><td>POL</td><td>1201.5</td></tr> <tr> <td>8</td><td>ISR</td><td>1187.5</td></tr> <tr> <td>9</td><td>CAN</td><td>1168</td></tr> <tr> <td>10</td><td>VNM</td><td>1129.5</td></tr> </table> <spoiler summary="Complete list"> <table style="width:100%"> <tr> <th>Rank</th> <th>Team</th> <th>Score</th> </tr> <tr> <td>1</td><td>CHN</td>...

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The Andover Computing Open (TACO) 2023 Hello Codeforces! Phillips Academy CS club is proud to announce **The 2023 Andover Computing Open** (TACO)!! TACO consists of **two 75-minute rounds** with **5-6 problems**, and we offer **two divisions** — the **Beginner division** problems will be at the USACO Bronze/Silver level (Codeforces div2-3) and the **Advanced division** problems will be USACO Silver+ (Codeforces div1-2). The contests will be held online on Codeforces. The first and the second round will take place on [May 20th, 2023 at 1:45 PM EST](https://www.timeanddate.com/worldclock/fixedtime.html?msg=The+Andover+Computing+Open+%28TACO%29+2023&iso=20230520T1345&p1=43&ah=1&am=15) and [May 20th, 2023 at 3:30 PM EST](https://www.timeanddate.com/worldclock/fixedtime.html?msg=The+Andover+Computing+Open+%28TACO%29+2023+Round+2&iso=20230520T1530&p1=43&ah=1&am=15). Between the rounds, we have prepared app-building workshops for our participants to enjoy. And we have invited Prof. Brian Dean, the director of USACO to spea...

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Codeforces Round 891 (Div. 3) Hello Codeforces! We are pleased to invite you all to participate in [Codeforces Round 891 (Div. 3)](https://codeforces.me/contests/1857), which will start on [contest_time:1857]. 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, and the ratings recalculated - by default, only "trusted" participants are shown in the results table. We encourage participants with a rating of 1600+ not to create new accounts but to participate unofficially. Only [trusted participants](https://codeforces.me/blog/entry/59228) 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_ o...

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SG NOI 2023 Final — E. Toxic Gene Hello everyone, yesterday was SG NOI 2023 and I found an interesting problem which can be read here https://codebreaker.xyz/problem/toxic Been thinking about it for some time and I find some interesting observation(s) : - We can do these following strategy for query : ``` 1 2 2 3 3 3 3 4 4 4 4 4 4 4 4 ... ``` Basically ask `1` for $2^0$ times, `2` for $2^1$ times all the way to ask `7` for $2^6$ times - From that, we can determine 3 types of group : (I) group that consists of `Strong` and `Regular` bacteria (II) group that consists of `Regular` and `Toxic` bacteria (III) group that can be determined whose the `Strong` bacteria are <spoiler summary="How to do that?"> To distinguish between those three, we can do the following : (I) if all the bits are on (e.g. the sum of living bacteria is $2^7 - 1$) then it is group I (II) if all the bits are 0 (e.g. the sum of living bacteria is $0$) then it is group II (III) if the bits consists of 1 and 0 (...

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Educational Codeforces Round 155 [Rated for Div. 2] Hello Codeforces! On [contest_time:1879] [contest:1879] will start. Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="https://mirror.codeforces.com/blog/entry/51208">blog post</a>. 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 [user:adedalic,2023-09-23] Dalabaev, Ivan [user:BledDest,2023-09-23] Androsov, Maksim [user:Neon,2023-09-23] Mesch...

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ICPC 2023 Online Spring Challenge powered by Huawei <img src="/predownloaded/af/22/af228fee1abb015217d8c524de74898aeff36419.png" align="right" style="height: 280px;" alt="text"/> Hello, Codeforces! **UPD:** Challenge is over. You can find results [in this post](https://codeforces.me/blog/entry/115695) We are happy to invite you to an exciting online event: ICPC 2023 Online Spring Challenge powered by Huawei, which will start on [April 13, 2023, 11:00 UTC](https://www.timeanddate.com/worldclock/fixedtime.html?msg=ICPC+2023+Online+Spring+Challenge+powered+by+Huawei&iso=20230413T11&p1=1440). In this Challenge, you will have a unique chance: - to compete during 14 days online challenge - to solve 1 exciting problem prepared by 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! Everyone is welcome to participate. It is an individual competition. **ICPC 2023 Online Spring Challenge p...

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The 1st Universal Cup. Stage 9: Qingdao Hello Codeforces! The 9th Stage of the 1st Universal Cup is coming. It will be held from Mar 25th to 26th. The contest is based on an official ICPC Asia East-Continent regional contest. It has been used in the 2018 ICPC Asia Qingdao Regional Programming Contest, which was prepared by the [SUA Programming Contest Problem Setter Team](https://sua.ac/). Problem setters: [user:zimpha,2023-03-22], [user:sfiction,2023-03-22], [user:J.T.J.L.,2023-03-22], [user:shb123,2023-03-22], [user:TsReaper,2023-03-22], [user:reku,2023-03-22], [user:fengsuiyan,2023-03-22], [user:ZhouYuChen,2023-03-22], [user:MudCoal,2023-03-22], [user:NeverLand.Dai,2023-03-22]. Testers: [user:chenjb,2023-03-22], [user:oipotato,2023-03-22], [user:Subconscious,2023-03-22], [user:lsmll,2023-03-22], [user:jiangshibiao,2023-03-22], [user:lzw4896s,2023-03-22]. As usual, we have three time windows for participating. You can participate in the contest in the following three time windows: * Mar 25th 13:00 &mdash; ...

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Latin American Regional Contests ICPC 2023 Teams Hello CF! **Next October 21st**, the regional contests in Latin America of the current ICPC cycle will be held simultaneously. These competitions will determine the teams that qualify for the Latin American Final. Although there is a list of the teams that will participate officially, I would love to know more about the competitors. What's your ICPC team in this edition? </br> <h1>All Teams with MaxRating</h1> <spoiler summary = "Open list"> <h1>All</h1> <table style="overflow: auto;"> <tr style="background-color: rgb(230, 224, 224);"> <th>Rank</th> <th>Name</th> <th>Country</th> <th>Member 1</th> <th>Member 2</th> <th>Member 3</th> <th>Rating</th> </tr> <tr style="background-color: rgb(255, 255, 255);"> <td>1</td> <td>teambrbr002</td> <td>Brazil</td> <td>[user:fmota,2023-10-16]</td> <td>[user:emaneru,2023-10-16]</td> <td>[user:MvKaio,2023-10-16]</td> <td>2662.6438</td> </t...

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Invitation to Goodbye Renyin Hello, Codeforces! It’s our pleasure to invite you to [Goodbye Renyin](https://uoj.ac/contest/80), which takes place on [Friday, January 20, 2023 at 13:00<sup title="timezone offset" style="font-size:8px;">UTC+8</sup>](https://www.timeanddate.com/worldclock/fixedtime.html?msg=The+contest+will+hold+at&iso=20230120T13&p1=33&ah=5). You will have 5 hours to solve 5 problems sorted roughly by difficulty. Each problem is worth 100 points and may have several subtasks. There might be interactive or output-only problems. The contest is open to everyone, though Codeforces-Div. 1-level contestants are more likely to enjoy it. For details, you may check last year’s [Goodbye Xinchou](https://uoj.ac/contest/74) (only available in Chinese, Simplified). The problems are authored by [user:changruinian2020,2023-01-17], [user:ix35,2023-01-17], [user:flowerletter,2023-01-17], [user:Melania,2023-01-17] and [user:qingyu,2023-01-17]. The competition format will be similar to (but a bit different...

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Invitation to TheForces Round #26 (Readall-Forces, TheForces-Rated, Prizes!) Hello, Codeforces! We are happy to invite you to [**TheForces Round #26 (Readall-Forces)**](https://codeforces.me/contestInvitation/9975a3db598ae549fd0f1f0a3107d6d064b1c140), which will take place on **[contest_time: 104802]**. As you can see in the subtitle, you are highly encouraged to **read all the problems!** <spoiler summary="What is TheForces Round?"> TheForces Rounds are series of educational contests for beginners to masters which are created by a group of CP lovers in the CF community. You can join our discord server with more than 1000 members for more information about the contests : https://discord.gg/h9N2vGmwep You will have **150 minutes** to solve **7 problems**. The round is **TheForces rated**! After the round you can find your rating changes [here](https://theforces.netlify.app/leaderboard). **Prizes**: the participant in the $i$th place will receive $2^{3-i}$ dollars $(1 \leq i \leq 3)$ as a prize. In addition, we will randomly select $\lfloor \frac...

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The 2nd Universal Cup. Stage 8: Guilin Hello! I'm happy to announce The 2nd Universal Cup. Stage 8: Guilin, which will be held on November 4th, 2023. The Regionals of the ICPC in the Asia East Continent and the CCPC National Sites have been taking place. The following stages of the Universal Cup (including Stage 8, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, 21, and 22) are all based on the ICPC Asia East Regionals/Semifinals and CCPC Sites/Finals. The schedule might be adjusted if there are possible conflicts with those regionals. This contest is prepared by Zhejiang University, which has already been used as The 9th China Collegiate Programming Contest Guilin Site. You can participate in the contest in the following time windows: * 02:00 (UTC) on Saturday &mdash; 07:00 (UTC) on Saturday * 05:00 (UTC) on Saturday &mdash; 10:00 (UTC) on Saturday * 08:00 (UTC) on Saturday &mdash; 13:00 (UTC) on Saturday * 11:00 (UTC) on Saturday &mdash; 16:00 (UTC) on Saturday * 13:00 (UTC) on Saturday &mdash; 18:00 (UTC) ...

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Invitation to TheForces #25 (5^2-Forces, TheForces-Rated, Prizes!) Hello, Codeforces! We are glad to invite you to [**TheForces Round #25 (5^2-Forces)**](https://codeforces.me/contestInvitation/f2a8e94a92234cb0d130fba154dd7291dbec6064), which will take place on **[contest_time: 104743]** You will be given **6 problems** and **2 hours** to solve them.<br> The round is **TheForces rated**! After the round you can find your rating changes [here](https://theforces.netlify.app/leaderboard). **Prizes**: the participant in the $i$th place will receive $2^{3-i}$ dollars $(1 \leq i \leq 3)$ as a prize. In addition, we will randomly select $\lfloor \frac{p}{30} \rfloor$ lucky participants and give each of them $1$ dollar as a prize, where $p$ is the number of participants. Please actively participate! You can get more information about **theforces rating** and **prizes** in **[our discord server](https://discord.gg/h9N2vGmwep)**. We want to thank: - [user:physics0523,2023-10-27], [user:wuhudsm,2023-10-27] $-$ for coordinating the round. ...

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The 1st Universal Cup. Stage 2: Hong Kong Hello! I'm happy to announce The 1st Universal Cup. Stage 2: Hong Kong, which will be held on Feb 4th, 2023. This contest is prepared by Zhejiang University, which has already been used as the The 47th ICPC Asia Hong Kong Regional Contest. There are 127 teams participating in the Regional. This contest also serves as Day 3 in 2023 Winter Petrozabodsk Camp on Feruary 2nd, 2023. The contest will start soon. You can participate in the contest in the following three time windows: * Feb 4th 13:00 &mdash; 18:00 (UTC +8) * Feb 4th 19:00 &mdash; 24:00 (UTC +8) * Feb 5th 02:00 &mdash; 07:00 (UTC +8) Please note that you can see two scoreboards in DOMjudge. The 'Local Scoreboard' shows the standings ONLY IN THE CURRENT TIME WINDOW. And the 'Combined Scoreboard' shows all participants, including the onsite participants, and the cup participants in the previous time windows. Authors: [user:Claris,2023-02-02], [user:Heltion,2023-02-02], [user:suika_predator,2023-02-02], [user:oipo...

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2nd Universal Cup. Stage 6: Warsaw Hello Codeforces! I wanted to invite you to participate in the 6th Stage of the 2nd Universal Cup, which will be held from October 21st to 22nd. The contest is made of problems from the finals of Potyczki Algorytmiczne (a.k.a. Algorithmic Engagements) from the last couple of years, which is the biggest open polish programming competition. There will be two such contests held as Universal Cup stages and in the upcoming weekend you'll be able to face the first of them. If you participated in any of the PA2020, PA2021, PA2022 or PA special edition **finals**, or happen to know the problems, please don't compete in this contest. Problems used in the upcoming contest are authored by me and [user:mnbvmar,2023-10-16]. Also a huge round of applause for [user:kostka,2023-10-16], who helped a lot in organization of each edition of PA, coordinated this contest and translated all the statements! You can participate in the contest in the following time windows: - 02:00 (UTC) on S...

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Codeforces Round #868 (Div.2) Hello! On [contest_time:1823] we will host [contest:1823]. The problems were written and prepared by [user:Igor_Parfenov,2023-04-21]. I would like to thank everyone who made this round possible: - [user:awoo,2023-04-21], [user:madlogic,2023-04-21], [user:_Israel_,2023-04-21], [user:Vectors_Master,2023-04-21], [user:BabaVoss,2023-04-21], [user:AlperenT,2023-04-21], [user:FzArK,2023-04-21], [user:Dominater069,2023-04-21], [user:m0t9_,2023-04-21], [user:rui_er,2023-04-21], [user:aryan12,2023-04-21], [user:purp4ever,2023-04-21], [user:mahersefo,2023-04-21], [user:Shawerma,2023-04-21], [user:maomao90,2023-04-21], [user:satyam343,2023-04-21], [user:errorgorn,2023-04-21], [user:Glemhel,2023-04-21] for testing the round and providing feedback to the problems - [user:adedalic,2023-04-21], for coordination of the round - [user:MikeMirzayanov,2023-04-21], for Codeforces and Polygon platforms - All participants This round will be **rated for participants with rating lower than 21...

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UT Open (UTOPC) 2023  Hello, Codeforces! [UTPC](https://www.cs.utexas.edu/users/utpc/index.html), the competitive programming organization at the University of Texas at Austin, is happy to invite you to participate in the 2023 edition of the UT Open (UTOPC) which will be held on [Saturday, April 15, 2023 at 1:00PM UTC-5 (CDT)](https://www.timeanddate.com/worldclock/fixedtime.html?iso=20230415T13&p1=24). You will be given 14-17 problems and 5 hours to solve them, with standard ICPC scoring. There will be a wide range of difficulties -- anyone is welcome to participate! This is a **team** contest, meaning that you are allowed to compete in teams of up to 3 members (it is totally acceptable to compete without teammates as well). This is (of course) not an official Codeforces round, and is thus unrated. Prizes will be available to students competing in person in Austin (at the Gates-Dell Complex), and further prize information i...

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Invitation to TheForces Round #27 (3^3-Forces, TheForces-Rated, Prizes!) Hello, Codeforces! We are happy to invite you to [**TheForces Round #27 (3^3-Forces)**](https://codeforces.me/contestInvitation/461c0cbd6ae0d9ebe01c5c23c65f0ae56a11e76b), which will take place on **[contest_time: 104855]** [Editorial](https://codeforces.me/blog/entry/123192) is out! <spoiler summary="What is TheForces Round?"> TheForces Rounds are series of educational contests for beginners to masters which are created by a group of CP lovers in the CF community. You can join our discord server with more than 1000 members for more information about the contests : https://discord.gg/h9N2vGmwep You will have **120 minutes** to solve **6 problems**. **Note**:there is an **interactive problem** in this round. If you are unfamiliar with interaction problems,you can read the guide for interactive problems [here](https://codeforces.me/blog/entry/45307). The round is **TheForces rated**! After the round you can find your rating changes [here](https://theforces.netlify.ap...

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MIT Informatics Tournament 2024 Finals -- Online Mirror **UPDATE:** The mirror will be delayed by 10 minutes. **When the contest is available it will be [here](https://codeforces.me/group/UqOrh5VnfT/contests).** Hello Codeforces! We ([user:duality,2023-10-25], [user:antontrygubO_o,2024-04-16], [user:SHZhang,2024-03-31], [user:rqi,2023-11-06], [user:Tlatoani,2023-11-06], [user:enoone,2021-04-24], [user:codetiger927,2023-10-25], [user:czhang2718,2023-10-25], [user:bensonlzl,2020-02-03], [user:innocentkitten,2024-04-01], [user:keta_tsimakuridze,2023-10-25], [user:kingofpineapples,2023-11-06], [user:SuperJ6,2024-03-31], [user:flamestorm,2024-04-17] ), current students at MIT, are excited to announce the final round of the [MIT Informatics Tournament 2024 Spring Invitational](https://codeforces.me/blog/entry/127830) is on [May 11th, 2024, 10:30AM-1:30PM Eastern Time](https://www.timeanddate.com/worldclock/fixedtime.html?msg=MIT+Informatics+Tournament+2024+Spring+Invitational+Finals&iso=20240511T1030&p1=797&ah=3). There will be an onli...

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Results of ICPC 2023 Online Spring Challenge powered by Huawei <img src="/predownloaded/da/0d/da0d971227243d43cc1c6abf2f3f49b18a465b81.png" align="right" style="height: 200px;margin: 10px 20px 20px;" alt="text"/> Hello Codeforces! We are glad to announce the completion of the **ICPC 2023 Online Spring Challenge powered by Huawei** and announce its results. We hope you enjoyed the challenges. All tests are completed, and the [results](https://codeforces.me/contest/1813/standings) are final! We remind all winners that you must have an account at https://icpc.global/ in order to receive a prize. Please ensure you register on ICPC system using the same email as your Codeforces account no later than Fri, May 5th. We are happy to introduce the winners of the challenge: - [user:nweeks,2023-05-01] - [user:Nanored,2023-05-01] - [user:T1024,2023-05-01] - [user:matheusaires095,2023-05-01] - [user:DimaTomsk,2023-05-01] - [user:baguabagau,2023-05-01] - [user:Sung.An,2023-05-01] - [user:Rebelz,2023-05-01] - [user:Rogerup,2023-05-01] - ...

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Educational Codeforces Round 151 [Rated for Div. 2] Hello Codeforces! On [contest_time:1845] [contest:1845] will start. Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="https://mirror.codeforces.com/blog/entry/51208">blog post</a>. 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 [user:adedalic,2023-06-28] Dalabaev, Ivan [user:BledDest,2023-06-28] Androsov, Maksim [user:Neon,2023-06-28] Mesch...

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Codeforces Round #904 (Div. 2) Hello, Codeforces! I am happy to invite you to my [contest:1884] which will be held at [contest_time:1884]. <b>The round will be rated for all the participants with rating strictly less than 2100</b>. The tasks were created and prepared by [user:74TrAkToR,2023-10-19]. I would like to thank everyone who helped me a lot with round preparation. <ul style="list-style-type:square"> <li>Coordinator [user:irkstepanov,2023-10-19] for excellent communication and help with preparation.</li> <li>Testers [user:Golovanov399,2023-10-19], [user:tibinyte,2023-10-19], [user:Silver_Fox,2023-10-19], [user:Illumina,2023-10-19], [user:eeeDA,2023-10-19], [user:coder8080,2023-10-19], [user:valeriu,2023-10-19], [user:XaRDKoDblCH,2023-10-19], [user:cristi_tanase,2023-10-19], [user:pshat,2023-10-19], [user:Vladosiya,2023-10-19], [user:DIvanCode,2023-10-19], [user:nnv-nick,2023-10-19], [user:priyanshu.p,2023-10-19] for high-quality testing and valuable advices.</li> <li>[user:AlFlen,2023-10-19] for...

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Educational Codeforces Round 157 [Rated for Div. 2] Hello Codeforces! On [contest_time:1895] [contest:1895] will start. Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="https://mirror.codeforces.com/blog/entry/51208">blog post</a>. 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 [user:adedalic,2023-11-02] Dalabaev, Ivan [user:BledDest,2023-11-02] Androsov, Maksim [user:Neon,2023-11-02] Mesch...

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Codeforces Round #863 (Div. 3) Hello! [contest:1811] will start at [contest_time:1811]. 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**. 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](https://codeforces.me/blog/entry/59228) 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 thi...

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Invitation to Replay of JU BitFest Season One 2023 Hello Codeforces! We ([user:twoplusthree,2023-05-28], [user:VS-Codes,2023-05-28], [user:Anupam_Ghosh,2023-05-28] and [user:om_mittal7,2023-05-28]) are glad to invite everyone to [Replay of JU BitFest Season One 2023](https://codeforces.me/contests/445869) which is scheduled on [contest_time:445869]. BitFest is an annual ICPC-style Programming Contest organised for freshers and sophomores of Jadavpur University. This year marked the very first edition of this contest, which consisted of two rounds &mdash; online Prelims and on-site Finals. We hope you like the problems we have created! You will be offered **$10 - 15$ problems** (from the combined problemset of both the rounds), and **$4$ hours** to solve them. You may participate alone, or in teams of not more than $3$ people. The problems vary in difficulty, ranging from **Easy** to **Intermediate**. Some of the problems may also require a classical solution. Note that the contest is **unrated**. We would also like to than...

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Invitation to TheForces Round #24 (DIV3-Forces, TheForces-Rated, Prizes!) Hello, Codeforces! We are happy to invite you to [**TheForces Round #24 (DIV3-Forces)**](https://mirror.codeforces.com/contestInvitation/143c52068d5bb4ccff419dc669e30fccd976aca0), which will take place on **[contest_time: 104683]** <spoiler summary="What is TheForces Round?"> TheForces Rounds are series of educational contests for beginners to masters which are created by a group of CP lovers in the CF community. You can join our discord server with more than 1000 members for more information about the contests : https://discord.gg/h9N2vGmwep You will have **135 minutes** to solve **7 problems**. The round is **TheForces rated**! After the round you can find your rating changes [here](https://theforces.netlify.app/leaderboard). **Prizes**:the participant who ranked $i$ will received $(6-i)$ dollars $(1 \leq i \leq 6)$ as a prize.In addition,we will randomly select $5$ lucky participants and give them $1$ dollar as a prize.Please actively participate! (We only support...

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2023 Girls Programming League Hello Codeforces! The Harker Upper School's Programming Club would love to invite middle school and high schoolers to our Girls Programming League (GPL) 2023 **virtual competitive programming contest on Saturday, September 16 from 8:45 AM to 2:30 PM PST**. The Girls Programming League is a one-day event comprising a programming contest, panel discussion, and awards, with the goal to inspire and empower women to participate in computer science, technology, and AI. Our theme this year is “Computer Science and Artificial Intelligence,” which we believe is a rapidly growing field that has important impacts and fascinating applications to explore. There will be **two divisions: novice and advanced**. The contest is open to all middle and high school students identifying as female or non-binary. Students can form **teams of up to 3**. We will also be awarding monetary prizes, in the form of Amazon gift cards, to the top 3 teams of each division. We'll also be featuring a panel...

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The 1st Universal Cup. Stage 14: Ranoa Hello Codeforces! The 14th Stage of the 1st Universal Cup is coming. It will be held from Apr 29th to 30th. The contest was used in the Osijek Competitive Programming Camp 2023 Winter. If you have solved any problems from the last day of the camp, please skip this round. Teams that participated in the camp can have their camp results included in the final standings. All problems are authored and prepared by me. I want to thank - all testers for greatly improving the quality of the contest: [user:edenooo,2023-04-28] [user:brunovsky,2023-04-28] [user:-is-this-fft-,2023-04-28] [user:ainta,2023-04-28] [user:nweeks,2023-04-28] [user:fishy15,2023-04-28] [user:QuickSortTLE,2023-04-28] [user:nmnsharma007,2023-04-28] [user:TAMREF,2023-04-28], - Osijek Camp organizers for hosting such an amazing camp, and - Universal Cup committee for providing the opportunity to share this contest with a wider audience. As usual, we have three time windows for participating. You can participate...

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INVITATION to TheForces Round #8 (ICPC-Forces) [MASHUP] [GYM] Hello, Codeforces! We are happy to invite you to [**TheForces Round #8 (ICPC-Forces)**](https://codeforces.me/contestInvitation/174e5174da816ccfed22ab867830836ad732692b), which will take place on **[contest_time:433200]** As it's an Indian ICPC week we tried to prepare one good team-based contest which can help you for ICPC preliminary round. You will have **3 hours** to solve **11 problems**. The problems are not sorted by difficulty. - Problems were prepared by [user:Psychotic_D,2023-01-11] and [user:dbtalaviya,2023-02-06]. - Would like to thank our testers: [user:merlin_,2023-03-16], [user:Little_Sheep_Yawn,2023-03-16], [user:dhru008,2023-03-16], [user:jubhai,2023-03-16], [user:_prince,2023-03-16], [user:endlessdreams,2023-03-16] - Also we want to thank **you** for participating in our round. You also can participate as a team. **The top places will be published after the contest.** **[Discord Group](https://discord.gg/hYn2CbtQ) (500+ people)** **[Conte...

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2022-2023 Winter Petrozavodsk Camp, Day 4: KAIST+KOI Contest Hello! I uploaded [2022-2023 Winter Petrozavodsk Camp, Day 4: KAIST+KOI Contest](https://codeforces.me/gym/104345) to the CF Gym. Problems are from KAIST 12th ICPC Mock Competition, with the exception of A, B (KOI 2022 Finals), and C (hard to explain). Problems are authored by: * ABC: [user:ko_osaga,2023-05-05] * D: [user:circle-oo,2023-05-05], [user:queued_q,2023-05-05] * EKL: [user:mo_onrabbit2,2023-05-05] * F: [user:mo_onrabbit2,2023-05-05] [user:gs18115,2023-05-05] [user:retro3014,2023-05-05] * GI: [user:gs18115,2023-05-05] * J: [user:queued_q,2023-05-05] * HM: [user:kclee2172,2023-05-05] I could be wrong, and I wish I am, but it feels like this is the last camp contest I will organize. Hope you had fun participating in the contest, as much as I enjoyed preparing the contest so much! <spoiler summary="List of relevant previous contests"> * [XVIII Open Cup. GP of Korea](https://codeforces.me/blog/entry/57528) * [KAIST RUN Spring Contest 2018](https://...

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Educational Codeforces Round 145 [Rated for Div. 2] Hello Codeforces! On [contest_time:1809] [contest:1809] will start. Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="http://codeforces.me/blog/entry/51208">blog post</a>. 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 [user:adedalic,2023-03-19] Dalabaev, Ivan [user:BledDest,2023-03-19] Androsov, Maksim [user:Neon,2023-03-19] Mescheryakov ...

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Syrian IOI Camp - July 2023 Hello everyone! I'm just back from Syria. I was holding a camp for the Syrian team going to IOI 2023 for a week there. First, let me use the opportunity to thank the hospitable people who hosted this camp. The camp was hosted by the Distinction and Creativity Agency (DCA). They tried out of their capacity for hosting the event as best as possible. Although Syria is not a rich and developed country, they pay attention to the Olympiad and their talents. They welcomed me in the best way and planned for some excursions and more. The members of the Syrian team are [user:Wael_Zaiback,2023-07-22], [user:aminsh,2023-07-22], [user:BERNARB.01,2023-07-22], [user:NeroZein,2023-07-22]. Almost all of them were super intelligent but without much knowledge. This is normal for a country without an Olympiad system and structure. <br> <center> <img width="50%" src="/predownloaded/39/ef/39ef7d5f85cbed60723bcec703118c0345530b59.jpg"> </center> <br> Because of that, I tried to cover...

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Results of the month Hello, Codeforces! A month ago, I started working part-time with [user:MikeMirzayanov,2023-10-02]. It's time to share the results of the first month! Overall, I've been involved in several things: - Added [contest:104633] and a series of Google Code Jam contests to the training section. - Assisted [user:MikeMirzayanov,2023-10-02] in detecting cheaters in several rounds. - And, of course, coordinated [contest:1872] and [contest:1878]. Also, all Div. 3 rounds for October are already prepared and in the testing stage! <spoiler summary="Full list of GCJ contests I added"> - [contest:104550] - [contest:104551] - [contest:104560] - [contest:104563] - [contest:104564] - [contest:104565] - [contest:104568] - [contest:104569] - [contest:104579] - [contest:104581] - [contest:104582] - [contest:104584] - [contest:104585] - [contest:104590] - [contest:104591] - [contest:104592] - [contest:104593] - [contest:104594] - [contest:104595] - [contest:104610] - [contes...

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Educational Codeforces Round 147 [Rated for Div. 2] Hello Codeforces! On [contest_time:1821] [contest:1821] will start. Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="http://mirror.codeforces.com/blog/entry/51208">blog post</a>. 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 [user:adedalic,2023-04-19] Dalabaev, Ivan [user:BledDest,2023-04-19] Androsov, Maksim [user:Neon,2023-04-19] Mesche...

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Educational Codeforces Round 158 [Rated for Div. 2] Hello Codeforces! On [contest_time:1901] [contest:1901] will start. Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="https://mirror.codeforces.com/blog/entry/51208">blog post</a>. 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 [user:adedalic,2023-11-23] Dalabaev, Ivan [user:BledDest,2023-11-23] Androsov, Maksim [user:Neon,2023-11-23] Mesch...

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2022-2023 Winter Petrozavodsk Camp, Day 2: GP of ainta Hello! I uploaded [2022-2023 Winter Petrozavodsk Camp, Day 2: GP of ainta](https://codeforces.me/gym/104427) to the CF Gym. It is the collection of problems authored by [user:ainta,2023-06-12] in 2015-2022. This contest is not related to me, I'm just stealing his contribution points. Thanks to [user:tlwpdus,2023-06-12], who found a solution to one of the problems. Enjoy! <spoiler summary="List of relevant previous contests"> * [XVIII Open Cup. GP of Korea](https://codeforces.me/blog/entry/57528) * [KAIST RUN Spring Contest 2018](https://codeforces.me/blog/entry/59625) * [XIX Open Cup. GP of Korea](https://codeforces.me/blog/entry/62435) * [XIX Open Cup. GP of Daejeon](https://codeforces.me/blog/entry/66883) * [XX Open Cup. GP of Korea](https://codeforces.me/blog/entry/70510) * [2020-2021 Summer Petrozavodsk Camp, Day 6: Korean Contest](https://codeforces.me/blog/entry/88406) * [XXI Open Cup. GP of Korea](https://codeforces.me/blog/entry/83511) *...

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The 1st Universal Cup. Stage 15: Hangzhou Hello! I'm happy to announce The 1st Universal Cup. Stage 15: Hangzhou, which will be held on May 6th, 2023. This contest is prepared by Zhejiang University, which is based on The 20th Zhejiang Provincial Collegiate Programming Contest, The 20th Zhejiang University of Technology Collegiate Programming Contest and The 16th Hangzhou Normal University Programming Contest. If you have participated in any of these contests or solved any problem from these contests, please skip this round. As usual, we have three time windows for participating. You can participate in the contest in the following three time windows: * May 6th 13:00 &mdash; 18:00 (UTC +8) * May 7th 19:00 &mdash; 24:00 (UTC +8) * May 7th 02:00 &mdash; 07:00 (UTC +8) Please note that you can see two scoreboards in DOMjudge. The 'Local Scoreboard' shows the standings ONLY IN THE CURRENT TIME WINDOW. And the 'Combined Scoreboard' shows all participants, including the onsite participants, and the cup participants in ...

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The 1st Universal Cup. Stage 3: Poland Hello everyone! The 3rd Stage of the 1st Universal Cup: Poland, will be held on Feb 11th, 2023. The contest was used in the [Akademickie Mistrzostwa Polski w Programowaniu Zespołowym (AMPPZ) 2022](https://amppz.tcs.uj.edu.pl/), which was hosted by Jagiellonian University. Authors: [user:paladin,2023-02-11], [user:krismaz,2023-02-11], Krzysztof Kleiner, Daniel Goc, [user:Kasia,2023-02-11], [user:kpw29,2023-02-11], Michał Woźny Special thanks to [user:kostka,2023-02-10], who coordinated the contest and gave us a huge help for setting the problems to make it possible as a Universal Cup stage. And thanks to Lech Duraj, the head of the jury of the AMPPZ, provides the contest materials and helps us to use them. The contest will start soon. You can participate in the contest in the following three time windows: * Feb 11th 13:00 &mdash; 18:00 (UTC +8) * Feb 11th 19:00 &mdash; 24:00 (UTC +8) * Feb 12th 02:00 &mdash; 07:00 (UTC +8) Please note that you can see two scoreboa...

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Educational Codeforces Round 154 [Rated for Div. 2] Hello Codeforces! On [contest_time:1861] [contest:1861] will start. Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="https://mirror.codeforces.com/blog/entry/51208">blog post</a>. 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 [user:adedalic,2023-08-30] Dalabaev, Ivan [user:BledDest,2023-08-30] Androsov, Maksim [user:Neon,2023-08-30] Mesch...

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Educational Codeforces Round 152 [Rated for Div. 2] Hello Codeforces! On [contest_time:1849] [contest:1849] will start. Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="http://codeforces.me/blog/entry/51208">blog post</a>. 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 [user:adedalic,2023-07-26] Dalabaev, Mikhail [user:awoo,2023-07-26] Piklyaev, Maksim [user:Neon,2023-07-26] Mescheryakov and ...

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Educational Codeforces Round 144 [Rated for Div. 2] Hello Codeforces! On [contest_time:1796] [contest:1796] will start. Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="http://codeforces.me/blog/entry/51208">blog post</a>. 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 [user:adedalic,2023-02-27] Dalabaev, Vladimir [user:vovuh,2023-02-27] Petrov, Ivan [user:BledDest,2023-02-27] Androsov, Ma...

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Invitation to TheForces Round #15 (Yummy-Forces) Hello Codeforces!! We're honored to invite you to **[TheForces Round #15 (Yummy-Forces)](https://codeforces.me/contestInvitation/5ce5fa91d702d465b1f7411809df4bf2120af6e9)** which will take place on **[contest_time:104408]**. <spoiler summary="What is a TheForces Round?"> TheForces Rounds are series of **unrated contests** which are created by a group of CP lovers in the CF community. You can join our discord server with more than 1000 members for more information about the contests: https://discord.gg/h9N2vGmwep </spoiler> **Don't forget the time, registration is open now!, sorry for the inconveniences, the problems are available + $5$ minutes extra time** You will have **2 hours and 15 minutes** to solve **6** problems. - Problems were prepared and authored by: [user:-kirito-,2023-06-03], [user:Parisa_Amiri,2023-05-21], [user:O--O,2023-06-03], [user:traverser_25,2023-06-03]. - Also huge thanks to our **ultrabig** army of testers: [user:physics0523,2023-06-03], [us...

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Educational Codeforces Round 148 [Rated for Div. 2] Hello Codeforces! On [contest_time:1832] [contest:1832] will start. Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="http://mirror.codeforces.com/blog/entry/51208">blog post</a>. 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 [user:adedalic,2023-05-11] Dalabaev, Ivan [user:BledDest,2023-05-11] Androsov, Maksim [user:Neon,2023-05-11] Mesche...

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The 1st Universal Cup. Stage 11: Shanghai (2022 ICPC EC Final) Hello Codeforces! The 11th Stage of the 1st Universal Cup is coming. It will be held from April 8th to 9th. It is also a replay of the 2022 ICPC East Continent Final Contest, which was held on March 24, 2023 &mdash; March 26, 2023. As usual, we have three time windows for participating. You can participate in the contest in the following three time windows: * [April 8th 13:00 &mdash; 18:00 (UTC +8)](https://www.timeanddate.com/worldclock/fixedtime.html?msg=The+1st+Universal+Cup.+Stage+11%3A+Shanghai+Time+Window+1&iso=20230408T13&p1=237&ah=5) * [April 8th 19:00 &mdash; 24:00 (UTC +8)](https://www.timeanddate.com/worldclock/fixedtime.html?msg=The+1st+Universal+Cup.+Stage+11%3A+Shanghai+Time+Window+2&iso=20230408T19&p1=237&ah=5) * [April 9th 02:00 &mdash; 07:00 (UTC +8)](https://www.timeanddate.com/worldclock/fixedtime.html?msg=The+1st+Universal+Cup.+Stage+11%3A+Shanghai+Time+Window+3&iso=20230409T02&p1=237&ah=5) Please note that you can see two scoreboards in DOMjudge. The 'L...

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The 2nd Universal Cup. Stage 12: Hefei Hello! I'm happy to announce The 2nd Universal Cup. Stage 12: Hefei, which will be held on December 2nd, 2023. This contest is an official ICPC Regional Contest — The 2023 ICPC Asia Hefei Regional Contest. The contest is prepared by University of Science and Technology of China. It is the second time for us to prepare the Hefei Regional Contest. <img src=/predownloaded/28/d5/28d55e3a8716fd59497c7d7036cd1b9aafc1ef08.jpg width=30% /> <img src=/predownloaded/86/55/86557d010b5d707c2b795ad3cead4ef1cc851d16.jpg width=30% /> <img src=/predownloaded/f4/ca/f4cadd036a3f15cd2571806e84a7bfdfd2168efe.jpg width=30% /> This is also my first time as a chief judge in an ICPC regional contest. Great thanks to the host school (University of Science and Technology of China) for preparing the Regional, and the hard work done by all staff and volunteers for this contest. The authors for preparing the contests: [user:Democy,2023-11-29], [user:Wallbreaker5th,2023-11-29], [user:zoxx,2023-11-29], ...

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2022-2023 ICPC, NERC, Southern and Volga Russian Regional Contest [Online Mirror, ICPC Rules] 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 [contest_time:1765], 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: [user:awoo,2022-11-23], [user:Neon,2022-11-23], [user:vovuh,2022-11-23], [user:adedalic,2022-11-23], [user:DmitryKlenov,2022-11-23], [user:dmitryme,2022-11-23], [user:DStepanenko,2022-11-23], [user:elena,2022-11-23] and [user:kuviman,2022-11-23]. Also, big thanks to the contest testers: [user:IlyaLos,2022-11-23], [user:Oleg_Smirnov,2022-11-23], [user:I_remember_Olya_ashmelev,2022-11-23], [user:p...

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Codeforces Round #883 (Div. 3) Hello, Codeforces! On [contest_time:1846] [contest:1846] will start. You will be offered **8 problems**, dedicated to the adventures of a restless mathematician, a programmer and just a funny character named **Rudolf**, and **2 hours 15 minutes** to solve them. Problems have 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. Note that the **penalty** for the wrong submission in this round is **10 minutes**. [Remember](https://codeforces.me/blog/entry/59228) that only the **trusted participants of the third division** will be included in the official standings table. This is a compulsory measure for ...

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Online mirror of The 2023 ICPC Asia Jakarta Regional Contest Hello Codeforces! We are going to hold The 2023 ICPC Asia Jakarta Regional Contest. We invite you to join the online mirror contest [2023-2024 ICPC, Asia Jakarta Regional Contest (Online Mirror, Unrated, ICPC Rules, Teams Preferred)](https://codeforces.me/contests/1906) on Codeforces. It will be held on [contest_time:1906] 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 2023 ICPC Asia Jakarta homepage](https://competition.binus.ac.id/icpc2023) * [The regional information in ICPC Global](https://icpc.global/regionals/finder/Jakarta) * [The onsite scoreboard](https://competition.binus.ac.id/contest/public) We hope that you will enjoy the contest. Good luck and have fun! **UPD.** The mirror has started! You can...

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Educational Codeforces Round 156 [Rated for Div. 2] Hello Codeforces! On [contest_time:1886] [contest:1886] will start. Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="https://mirror.codeforces.com/blog/entry/51208">blog post</a>. 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 [user:adedalic,2023-10-08] Dalabaev, Ivan [user:BledDest,2023-10-08] Androsov, Maksim [user:Neon,2023-10-08] Mesch...

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CAMA 2023 Editorial Hello everyone! Below is the editorial for the informatics division of CAMA along with the solution code to every problem. We have also uploaded PDFs with the editorial both in Spanish and English on [our website](https://www.camacontest.online/). The contest can be found on this [gym](https://codeforces.me/gym/104745). The problems were prepared by [user:Esomer,2023-11-05], [user:danx,2023-11-05], [user:Hectorungo_18,2023-11-05], [user:javiergm06,2023-11-05] and [user:Rigobertus,2023-11-05]. We would also like to thank our VIP tester [user:BernatP,2023-11-05] for his dedication towards the contest. ### [A. Saving the cinema](https://codeforces.me/gym/104745/problem/A) <spoiler summary="Solution"> You should do what the problem says with an if statement. Be careful to add the final dot. </spoiler> <spoiler summary="Code"> ~~~~~ #include <bits/stdc++.h> using namespace std; int main(){ string s; cin >> s; if(s == "Yoda") cout << "Pertenece a Star War...

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Bug in upvote system after integer underflow in Goodbye 2023? How did [Hello 2024 announcement blog](https://codeforces.me/blog/entry/124227) get 1000 upvotes **before** the contest even started &#129322; ? Is 4000 downvotes on Goodbye 2023 too much for codeforces to handle so upvotes on other blogs scale exponentially now &#x1F914; ? I mean... I don't mind but it's kind of funny that I am now one of the top 10 contributors because of Hello 2024 &#129313; . Maybe this blog will get another 1000 upvotes &#128513;

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Contest Based on Brain Craft Intra SUST Programming Contest 2023 Hello, Codeforces! The flagship contest of SUST is here everyone! There will be 12 problems and the problemset is based on **Brain Craft Intra SUST Programming Contest 2023**. We cordially invite you to participate in this contest. Also, we encourage you to participate as teams. Please make sure that you read ALL the problems! The contest will be held on [contest_time:104283] and will run for 5 hours. The setters of this contest are: [user:Alfeh,2023-04-06], [user:Kawchar85,2023-04-06], [user:Mac_prime,2023-04-06], [user:magic_kiri,2023-04-06], [user:nh_nayeem,2023-04-06], [user:Raiden,2023-04-06], [user:ShikariSohan,2023-04-06], [user:ShinnirKolaChori,2023-04-06], [user:susmoydhar7,2023-04-06], [user:Tahseen,2023-04-06] Contest link: [Contest Based on Brain Craft Intra SUST Programming Contest 2023](https://codeforces.me/contests/104283) **UPD:** Congratulations to the winners of the round! Top 5 of all participants: <table style="border-collapse:collapse;borde...

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Happy New Year! **Hello guys!** **The new year is coming to an end, so I wish everyone a happy New year!** This post is the [conclusion](http://codeforces.me/blog/entry/108044) of this mini-competition, just summing up the results :). In the last post, I couldn't mention everyone who left their comments, but I hope I didn't forget about anyone in this one! From below you can see how your rank has changed since the beginning of this mini-competition(Left one &mdash; Old, Right one &mdash; New), I hope that almost everyone has been able to achieve their goals, and those who have not achieved them will have another wonderful year for this! ### **Happy New Year Codeforces!** ### International grandmaster! [user:Vercingetorix,2022-10-17] • [user:Vercingetorix,2023-01-01]! ### Grandmasters! [user:jjang36524,2022-10-17] • [user:jjang36524,2023-01-01]! [user:SecondThread,2022-10-17] • [user:SecondThread,2023-01-01]! [user:anpoli99,2022-10-17] • [user...

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Educational Codeforces Round 143 [Rated for Div. 2] Hello Codeforces! On [contest_time:1795] [contest:1795] will start. Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="http://codeforces.me/blog/entry/51208">blog post</a>. 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 [user:adedalic,2023-02-15] Dalabaev, Vladimir [user:vovuh,2023-02-15] Petrov, Ivan [user:BledDest,2023-02-15] Androsov, Ma...

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Invitation to Pradnya 2023  Hello Codeforces! **Pune Institute of Computer Technology (PICT)** would like to invite you all to **Pradnya 2023**. **Pradnya** is a programming event that puts the programmer’s logical thinking and problem-solving skills to the test using programming languages. **Team Size:** Maximum 2 members **Date:** 21 to 23 April 2023 **Total Prize Pool:** 50000 INR + **Registration Fees For Indian Citizens:** 100/- INR per team **Registration Fees For Out of India Citizens:** 0/- INR per team **Eligibility Criteria:** - Junior Level: This category is open for all students who are pursuing first or second year of any undergraduate degree/course. - Senior Level: This category is open for all students who are pursuing third or final year of any undergraduate degree/course. Register (For Pradnya Event), FE/SE/TE/BE Coding Competition for National Entries (FOR INDIAN CITIZENS) https://pictin...

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The 1st Universal Cup. Stage 5: Osijek Hello everyone! The 5th Stage of the 1st Universal Cup: Osijek, will be held on Feb 25th, 2023. The problems have been written by me for use as Day 8 in [Osijek Competitive Programming Camp 2023](https://codeforces.me/blog/entry/110945) on February 25th, 2023. You can participate in the contest in the following three time windows: * Feb 25th 13:00 &mdash; 18:00 (UTC +8) * Feb 25th 19:00 &mdash; 24:00 (UTC +8) * Feb 26th 02:00 &mdash; 07:00 (UTC +8) Please note that you can see two scoreboards in DOMjudge. The 'Local Scoreboard' shows the standings ONLY IN THE CURRENT TIME WINDOW. And the 'Combined Scoreboard' shows all participants, including the onsite participants, and the cup participants in the previous time windows. Contest link: https://domjudge.qoj.ac/ Universal Cup Scoreboard: https://qoj.ac/ucup/scoreboard **About Universal Cup:** Universal Cup is a non-profit organization dedicated to providing trainings for competitive programming teams. Up to ...

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[GYM] Tishreen + SVU Collegiate Programming Contest 2023 Hello, Codeforces! I am happy to invite you to participate in [Tishreen + SVU Collegiate Programming Contest 2023](https://codeforces.me/gym/104487) which was held on Tuesday, June 20, 2023, at 11:00. The problems were authored and prepared by [user:Youstill_dontknowmeyet,2023-06-05], [user:OverSimpIified,2023-07-19], [user:MASTER_MOUF,2023-07-19], [user:purp4ever,2023-07-19], [user:FzArK,2023-07-19], [user:Geo_Ghaffar,2023-07-19], [user:Nihad_Nabelsi,2023-07-19], [user:Tinky-Winky,2023-07-19], [user:Ali_zaibug,2023-07-19], [user:Besher_Zaiback,2023-07-19], [user:mahersefo,2023-07-19], and me. I would like to thank our testers: [user:Vectors_Master,2023-07-19], [user:BabaVoss,2023-07-19], [user:Giggity-,2023-07-19], [user:Ayham_Dabah,2023-07-19], [user:Yousef-Elwan,2023-07-19], [user:Black_Bits,2023-07-19], [user:muso-ka,2023-07-19], [user:little-fermat,2023-07-19], [user:KoKai,2023-07-19], [user:Shawerma,2023-07-19], [user:Two_Pointer_it,2023-07-19], [user:Blue_this_yea...

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Invitation to Code Venture Hello Codeforces! We are glad to invite you to participate in a contest hosted by technical fest **Pragyan, NIT Trichy**, which will take place on **Thursday, 23rd March, from 5:30 PM to 7.10PM IST.** <br /> <br /> <br /> <center>  </center> <br /> <br /> **Pragyan**, in association with **Spider**, presents **Code Venture**. An competitive programming contest on Codechef which will go live on 23rd March from 5:30-7:10 pm. An 100 minute contest to test your problem solving and thinking abilities. Think you have what it takes to reach the top? Test your programming skills in a **beginner friendly contest**. The contest is unrated for everybody and common for all divisions. **CASH PRIZES Distribution** (Indian Participants): - Top 3 performers will be awarded cash prizes of INR 15000, 9000, and 6000, respectively. **Contest Link:** [CDVN23](htt...

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Educational Codeforces Round 159 [Rated for Div. 2] Hello Codeforces! On [contest_time:1902] [contest:1902] will start. Series of Educational Rounds continue being held as [Harbour.Space University](https://harbour.space/) initiative! You can read the details about the cooperation between [Harbour.Space University](https://harbour.space/) and Codeforces in the <a href="https://mirror.codeforces.com/blog/entry/51208">blog post</a>. 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 [user:adedalic,2023-12-02] Dalabaev, Ivan [user:BledDest,2023-12-02] Androsov, Maksim [user:Neon,2023-12-02] Mesch...

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[GYM] Invitation to Aleppo Collegiate Programming Contest 2023 V.2 Hello codeforces community! I am happy to invite you to participate in the [Aleppo Collegiate Programming Contest 2023 V.2](https://codeforces.me/gym/104544) (V.2 because the first version of the contest was dismissed, so this is version 2) that was held at Damascus University on [contest_time:459931]. The online training will be on codeforces gyms and will start on [contest_time:104544]. Thanks to [user:Kaitokid,2023-08-27], [user:AboAbdoMC,2023-08-27], [user:Prince_Kassad,2023-08-27], [user:Obada_Saleh,2023-08-27], [user:Giggity-,2023-08-27], [user:YazanAlattar,2023-08-27], [user:A.D.,2023-08-27], [user:Monkey.D.Luffy.,2023-08-27], [user:AboAImanaI,2023-08-27] and [user:radi__07,2023-08-27] for creating and preparing the contest. Special thanks to [user:Majedh,2023-08-27] and [user:Anas_Da,2023-08-27] who did most of the work. Thanks to [user:Baraa_Armoush,2023-08-27] and [user:HeMoo,2023-08-27] for their contribution and constructive feedback. Thanks to [user:Vectors_Ma...

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Refact.ai Match 1 (Codeforces Round 985, Div. 1 + Div. 2) Hello, Codeforces! We (KDOI Team) are glad to invite you to take part in [contest:2029], which is the 8th CP contest held by us! You can view the previous rounds by us [here](/blog/entry/135847). - Number of problems: $9$ ($0$ interactive); - Start time: [contest_time:2029]; - Contest duration: $180$ minutes; - Score distribution: $750-1250-1750-2250-2500-3000-3500-5000-5500$. The problems were authored and prepared by [user:Error_Yuan,2024-11-05], [user:wyrqwq,2024-11-05], [user:Otomachi_Una,2024-11-05] and me [user:sszcdjr,2024-11-05]. --- <img src="/predownloaded/73/e1/73e1593107761ee6b925164110aa7307488b2215.png" style="float:right; margin: 0 0 2em 2em; width:300px;"/> A few words from our sponsor: We’re [Refact.ai](https://refact.ai/?utm_source=codeforces&utm_medium=post&utm_campaign=round_09112024&utm_content=cf_short_09112024), an open-source AI Coding Assistant, and on November 9th, we’ll be hosting our first round on Codeforces! Winners will receive ...

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Northwestern Europe Regional Contest 2023: live broadcast schedule Hello, Codeforces! <img alt="NWERC 2023 logo" src="/predownloaded/93/50/9350bf3e0a5d44b0b686211a5b3c988b7643ecd6.png" style="height: 170.0px;max-width: 100.0%;max-height: 100.0%;" align="right"> We are glad to invite you to follow NWERC 2023! The 2023 Northwestern Europe Regional Contest will be held from the 24th till 26th of November 2023. The contest will be held on the campus of the Delft University of Technology, Netherlands. NWERC is an official regional contest of ICPC which draws students' teams from colleges and universities throughout all over the Northwestern part of Europe. The team that solves the most problems at the end of the contest qualifies for the ICPC World Finals 2024, which is planned on September 2024, Kazakhstan. There will also be an online spectator contest for you to solve the problems alongside the contestants. The contest will start at 10:30 CET on Sunday, November 26th. You can register at https://spectator.nwerc.eu/. Please join us on th...

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