Please, read this Hello, Codeforces. Friends. I apologize, but today I will be a bit chaotic and mix personal with public. It just happened that way, I'm sorry. Today, my mother passed away. It's hard for me to write this. Even just seeing it in text makes it feel like something from a nightmare. She was extraordinary. It's difficult for me to articulate it right now, but take my word for it. It felt like all the best qualities one could imagine in a mother converged in her. I don't know any other people so kind, sincere, non-judgmental, capable of love, listening, befriending, supporting, and taking joy in the world around them, and bringing joy to their loved ones. Mom, it's already hard without you, it feels empty. She had glioblastoma. It's an aggressive brain cancer that affects only a few people out of 100,000. I believe, I hope, that science will soon be able to tackle this disease. But for now, this diagnosis is a death sentence. Maybe some of you are or will be associated with medic...

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Congratulations: Tourist has reached a rating of 4000! Hello, As you may have already noticed, [user:tourist,2024-08-31] has reached the symbolic milestone of 4000 rating points. This is the first time in the history of competitive programming. I, personally, and the entire Codeforces team, congratulate Gennady [user:tourist,2024-08-31] Korotkevich on this incredible achievement! Right now, we have assigned a new rank “Tourist” to the 4+ rating. This highlights the uniqueness of the moment! However, in the future, I would like to change this name to something a bit more neutral (or leave it Tourist?). Would you help me with this? I’d appreciate your cool suggestions in the comments! Here are a few options from me. Please, vote: - Epic Grandmaster - Ultimate Grandmaster - Godlike Grandmaster - Tourist - 4K Grandmaster - Grandmaster 4K - Legendary Grandmaster 4K - Joke option: Ultra HD Grandmaster - from [user:Tlatoani,2024-08-30]: Champ...

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In Problems Statements, Example Inputs Are Now Highlighted if Test Cases Are Used <img src="/predownloaded/c1/64/c164a37e70461b3b6a0236b7e72c81c7f9b47d8d.png" style="width: 200px; float: right; margin: 1em 0 0 0;"/> Hello, Codeforces. Look what an interesting thing I've been working on the last few days. Now, if a problem uses test cases and its validator is written in the recommended way (using setTestCase), then the example inputs are displayed using different colors. Just follow the link and see how beautiful it turned out: <a href="https://mirror.codeforces.com/contest/1714/problems">https://mirror.codeforces.com/contest/1714/problems</a>! So far I have enabled this only for the last few rounds, but if everything works as intended, I will enable it for more rounds. In order to support this, I had to tinker a lot. I made changes to [testlib.h](https://github.com/MikeMirzayanov/testlib) so that the validator can return test markup. Support for this markup required changes in various system services. But I think it's worth it! The coolest thing is that it wa...

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Codeforces Round #712 omg hi! I am pleased to invite you to participate in [contest:1503] and [contest:1504]! You will be given **6 problems** and **2 hours 15 minutes** to solve them. I'm happy to announce the theme of this round is déjà vu! I would like to thank the following people: - <a class="rated-user user-red" href="https://images.emojiterra.com/twitter/512px/1f921.png" title="The Entire Circus">antontrygubO_o</a> for accepting all of my problems <span style="color:white;">at gunpoint</span> - <a class="rated-user user-orange" href="/profile/Nika_Tamliani" title="Useless Tester Nika_Tamliani">Nika_Tamliani</a>, <a class="rated-user user-violet" href="/profile/arvindr9" title="Useless Tester arvindr9">arvindr9</a>, <a class="rated-user user-red" href="/profile/dorijanlendvaj" title="Useful Tester dorijanlendvaj">dorijanlendvaj</a>, <a class="rated-user user-blue" href="/profile/I_Love_YrNameCouldBeHere" title="Useful Tester I_Love_YrNameCouldBeHere">I_Love_YrNameCouldBeHere</a>, <a class="r...

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Codeforces: Problem Difficulties Hi Codeforces! Meet a small innovation on Codeforces &mdash; difficulties of problems (and at the same time a new widget filtering problems in the archive). For all the problems of the archive, I’ve calculated the difficulties in the scale of the rating of participants. Approximately this means that if the rating of the problem is equal to yours, then on a typical round you would solve the problem with a probability of 0.5. And, in general, if your rating is $r_i$, and the problem rating is $r_j$, then the problem during the round can be solved approximately with probability: $$P_{i,j}=\frac{1}{1+10^{\frac{r_j-r_i}{400}}}.$$ For example, if the rating of a problem is less than yours by 200, then the expected probability of solving the problem is 0.75. With a difference of 400 rating points, the probability increases to 0.9. For convenient search of problems in the archive, you can now use a special widget: <center><img src = "/predownloaded/1c/fb/1cfba40476423720c79f0f...

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About the Failed Round 591/Technocup 2020 — Elimination Round 1 Hi Codeforces! Unfortunately, ill-wishers thwarted the round by making DDOS on our infrastructure. Neither the coordinator nor the writers of the round are subjects to blame for the failure. Please do not downvote the announcement of the round. I think that this situation is an additional reason to support the writers. They worked hard and prepared good problems! Apparently, such an attack should be regarded as a symptom of the fact that Codeforces outgrew the youth phase and entered serious adult life. Of course, we will respond with adequate measures to protect ourselves from such incidents. Fortunately, for almost 10 years of work, a large community has formed around those who care about Codeforces. We are not worried about possible additional expenses or efforts. We can do this. The rounds must go on. &mdash; [user:MikeMirzayanov,2019-10-06] **UPD 1:** All three of today's rounds will be unrated. **UPD 2:** Hooray! Today we've survived another DDOS attack. The round ...

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Codeforces: Soon We Will Change the Rating Calculation for New Accounts Hello everyone. In the coming days I will finish the implementation of small changes in the rating calculation for new accounts. Here are the main innovations. * The rating of the new account will be equal to $0$ for display (but it will be equal to $1400$ when calculating rating changes). * Suppose, after the first round, the participant gained $d_1$ rating points (remember that the rating was considered equal to $1400$ in such calculations), then in the rating display after this round $500+d_1$ will be displayed. Thus, after the first participation, the rating is likely to increase from $0$ to a value in the region of $500$ (plus or minus $300$ approximately). * Thus, before the second participation, the displayed rating is $500+d_1$, and the rating for calculating changes is $1400+d_1$. Suppose a new change is $d_2$, then the displayed rating becomes $500+d_1+350+d_2$. * Thus, before the third participation, the displayed rating is $500+d_1+350+d_2$, and the rating for calc...

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Codeforces: Our Steps After DDOS Attack Hello. As I wrote into a comment, last round we are faced with a strong DDOS-attack which ruined the competition. I don't know who did it, I also don't know reasons to do it. I'm very upset about the situation and ready to make an effort to be prepared for such issues. I spend a lot of time to be ready for such incidents. Here are steps you need to do to be ready for unexpected failures: * Join our telegram channel by the link https://t.me/codeforces_official to read urgent news. * Be sure that you know the password of your Codeforces account. If you don't remember it, just use <a href="https://mirror.codeforces.com/passwordRecovery">the password recovery feature</a>. Please, do it right now. * I've implemented a minimalistic website for replacing the main site in case of emergencies. Now you can only read problems, view your submissions (without any details), submit codes. Probably, later I'll add some more features, but anyway, the minimalistic version will have only vital fea...

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New Year's Eve Update: Random Problems for Mashups Hello, Codeforces! Only a couple of days remain until 2025. To wrap up the year, I'm bringing an update &mdash; I hope you'll find it useful. Now, you can automatically find and add random problems for your mashup based on a range of criteria and restrictions. The problems are sourced from the archive, and unusual problems are automatically excluded. So, click the "Add random problems" link under the problem list and proceed to the addition form. <center> <img style="zoom:75%;" src="/predownloaded/b9/25/b925e4d00215ff2e408cc81c2629936df72dce38.png"/> </center> Here's what you can do: * Exclude problems that registered mashup participants have solved/attempted/authored (a problem will be excluded if at least one registered participant is familiar with it), * If the mashup belongs to a group (e.g., your training group), exclude all problems from other contests in that group, * Exclude problems with subtasks &mdash; such problems are often interconnected or referenc...

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Rule Restricting the Use of AI [revision 2024-09-14] It seems that neural networks are working technological wonders. Not long ago, they struggled with even the simplest tasks in our competitions, but now they are reaching new heights that cannot be overlooked. There is reason to believe that progress will continue, and we can expect further advancements in neural networks within the realm of programming competitions. For this reason, we are explicitly limiting the use of AI-based systems (such as various models like GPT, Gemini, Gemma, Llama, Claude, and others) for solving programming problems. However, we recognize that AI can be a valuable tool for learning and coding assistance, so we aim to establish clear boundaries for its use. **Application of this Rule:**<br/>This rule applies strictly to in-contest participation. This includes both registered contestants and out-of-competition participants in any rated Codeforces round. If a round is unrated and this is explicitly stated in the round announcement or rules, the rul...

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Codeforces Round #639: the round is rescheduled Hello, Codeforces! Unfortunately, I report that I decided to reschedule this round. I'm afraid that something might go wrong. Some strange database behavior has appeared, which leads to slow operation in completely unexpected places (it never was and should not be). I will work hard to fix it. My recent tests show that this can dramatically increase judging time (and leads to a huge queue). I don't want to risk the efforts of the writer, the coordinator, testers, and your time. Sorry about it, I was trying to fix it for many hours but I need more time. Hope it will be a great round! Mike. **UPD 1:** I temporarily rescheduled it on May, 6. But I'll discuss the date with the writer and coordinator and reschedule it again to the date they want. **UPD 2:** [user:Monogon,2020-05-04] approved that [contest_time:1345] is good new date and time for the round. See you in 3 days! **UPD 3:** It seems I've fixed the issue. It turned that it was connected with [week ago incident](htt...

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Codeforces EDU: β-testing (Now in English!) <img src="/predownloaded/47/86/4786c2ec901c0b5b490794ca6fd5145f0dcdeae3.png" style="float:right; width: 400px; margin: 0 1em 1em 1em"/> Hello Codeforces! In February, in the Russian-language interface, we announced a new educational subsection of the website. It's time to go international! I am pleased to invite you to test the new section, which so far has the working title EDU. I hope that someday EDU will become a real educational hub for fans of programming competitions. It will be great to have in one place the collected educational content with text and video materials, with selected thematic problems. At the moment, its functionality is still under development, and here is the current progress and <i>β</i>-testing preview. Write your comments and suggestions in the comments here. <center style="margin:2.5em;"> <a href="/edu/courses" style="text-decoration:none; font-size:18px; background-color:#01579B; color:white; font-weight:bold; padding:0.5em 1em;">Go to EDU ...

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

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Goodbye 2019. Hello 2020! <img src="/predownloaded/85/58/8558df7ac8a1c33d501ea8fd9b18dd3d95886b90.png" style="width:290px; float:right; margin: 0 1.5em 1.5em 1.5em"/> I am happy to wish you a Happy New Year! I wish you a great, bright, interesting New Year! Just believe that it can become so: difficulties will be left behind, and ahead of you will be a joy of victories and discoveries. I wish all of us new interesting problems, records and achievements! Set new goals and be sure to try to achieve them! And do not go far, we will try to make your 2020 year more fun! I thank with all my heart for the contribution to the community of coordinators, problem writers, testers, and those who wrote interesting posts and comments. Many thanks to the sponsors, partners and customers: you help the community not to stand still, give the opportunity to hold interesting events. Thanks to all visitors to the website and just not indifferent. See you in the new year! &mdash; [user:MikeMirzayanov,2019-12-31]

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Goodbye 2020. Hello 2021! <img src="/predownloaded/f4/1f/f41ff0beb745fb2f84a55d9f2cc451273efc6267.jpg" style="width:300px; float:right; margin: 0 1em 1em 1em"/> Hello Codeforces! This unusual and difficult 2020 has come to an end! What will the new year be like? I wish all of us that we have the opportunity to meet in person so that the contests take place not only online. I ask you to think of something important and good. Let this wish come true! We have had a large number of rounds this year. I hope we have pleased you with interesting problems. Thanks to the round coordinators and writers! You make our community richer. Please make us happy in 2021! I wish the participants victories over yourself (and over problems!) and development of your skills, interest and curiosity! Hello, 2021! 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 onc...

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Codeforces: Updates in rating and rounds <img src="/predownloaded/21/a3/21a33b497ee8a34a678befc3f79745eb69a9cf07.png" style="float:right; margin: 0 1em 1em 1em;"/> Hello, Codeforces! It's time for news. I hope you will enjoy! * We reduce the rating bound for the orange color. Thus, now the orange rating (and the _Master_ title) will start from 2100 rating units. * The lower bound of the rating for _legendary grandmasters_ is increased to 3000 rating units. Thus, right now in the community, 14 participants meet this requirement. Real legends! * For rounds like "Div. 2 Only" the upper bound of the rating for official participation is increased. Now everyone whose rating is less than 2100 (i.e., before _masters_) will be able to register for such rounds to participate officially, their rating will be updated based on the results of the round. We do not plan to increase the complexity of Div. 2 rounds. Practice shows that the problems of such rounds are interesting and useful for participants "below the orange". ...

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Codeforces: С++17 64bit Support Hello, Codeforces. I hope you wash your hands and feel great. I added the support of 64-bit g++. If you are using Windows, you can easily install it via our minimalistic package manager [PBOX](http://pbox.me/) running the command line `pbox install msys2-mingw64-9`. Your solutions are compiled with the command line `g++ -static -DONLINE_JUDGE -Wl,--stack=268435456 -O2 -std=c++17 program.cpp`. Now you can try to use int128 and other 64-bit specific features! In fact, I am slightly worried that the presence of such features may widen the gap between C ++ and other languages. Wait and see. Currently, support for 64-bit C++ is experimental. For example, I would not be surprised if IO on it works slower in some cases (it is necessary to test!). I invite you to join the testing and experimentations. Share your impressions in the comments!

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My Reply on "Mike, please stop ignoring your userbase" This is a response to [this post](https://mirror.codeforces.com/blog/entry/141442). Originally, I intended to leave it as a comment, but the text turned out to be quite long. So I decided to publish it as a separate post. Hi! Let me start with the main idea: I don't think I ignore too many issues (though I do ignore some). In most cases, I do work on them, but these days I just don't feel like writing about it. That kind of communication takes a lot of energy &mdash; which I currently don't have. Oh, it looks like you edited the beginning of the blog, and now it triggers less of an internal protest in me. Honestly, lately I've been in a difficult emotional state, and I just don't have the energy or desire to interact much. It's not just about Codeforces &mdash; it's generally harder for me to engage than it used to be. I won't go into details (health, relocation, family issues, changes in the nature of my work due to bots) &mdash; all of that affects my mental state and willingne...

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Goodbye 2021. Hello 2022! <img src="/predownloaded/f4/1f/f41ff0beb745fb2f84a55d9f2cc451273efc6267.jpg" style="width:300px; float:right; margin: 0 1em 1em 1em"/> Hello Codeforces! Oh yes, 2021 ends! I recently realized that 2022 is pronounced like "2020 too". Not that. I want a completely different year! Anyway, we did a nice job this year. I hope we have pleased you with interesting problems. Thanks to the round coordinators and writers! You make our community richer. Please make us happy in 2022! I wish you all interesting tasks and brilliant solutions! I wish you error-free code and wish us only rated rounds :-) Hello, 2022! 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 han...

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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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Educational Codeforces Round 91 is ruined and unrated Hello. Unfortunately, the Educational Codeforces Round 91 round will be unrated and, actually, it was completely ruined. I don’t understand what happened yet. At some point in time, all systems began to work unstably and actually stopped working. So far I have no understanding what happened. You may have to change the schedule for future rounds. Sorry. We have such a black stripe. Very upset and demotivated. Mike.

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About the Round 382 Good afternoon! I've decided to share my thoughts on the round 382. Of course, it turned upset not only to me, but also to the round coordinator [user:GlebsHP,2016-11-28]. In this round the main negative feedback were caused by two problems: [problem:735D] and [problem:735C]. Regarding [problem:735D]. I do not share the criticism to this problem. In fact, to solve it would be nice to be familiar with <a href="https://en.wikipedia.org/wiki/Goldbach&apos;s_conjecture"> Goldbach's Conjecture</a> and better with <a href="https://en.wikipedia.org/wiki/Prime_number_theorem">Prime Number Theorem</a>. These facts are medium-popular in the world of programming contests. Familiarity with them is useful, gives useful insight into primes. It is important: in this problem it was necessary to perform a simple, but nevertheless, additional step to find solution. It seems to me that it's okay to use problems that have a reduction to some popular and semi-popular topics. Otherwise, it is th...

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New: Diagnostics of Solutions in C++ <img src = "/predownloaded/b5/d2/b5d246ffc32dfe82c3cbac77d1898c5fcb62fa57.jpg" style = "float: right; margin: 0 1em 1em 1em;"/> Hello! I am pleased to report that two rounds of Codeforces have gone quite well in terms of the work of Codeforces, I am very glad about it. These <s>days</s> nights I spent in a profiler, fixing the code, researching the settings of MariaDB. In addition, I managed to allocate several hours on Sunday (to be honest, until Monday morning) to finish the long-planned innovation. Meet, diagnostics of solutions in C++! Many Codeforces visitors are already tired of the questions of less experienced participants: "Why does my solution not work on some test on the Codeforces servers, if I locally launch it and it works correctly? You have the wrong compiler/servers!" In 99% of cases this is an example of <a href ="https://en.wikipedia.org/wiki/Undefined_behavior">undefined behavior</a> in a program. In other words, the program contains mistakes that, du...

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Codeforces New Feature: Rewrite Statements in Mashups Hello Codeforces! There is something new for you. It seems that now it will be easier to reuse problems from the archive for educational and other purposes. As you know, problems from past Codeforces rounds can be added to <a href="https://mirror.codeforces.com/blog/entry/10099">mashups</a> simply by their codes of the form like <code>1234D</code> (contest ID + problem letter). I myself regularly used this when I taught at Saratov University &mdash; it was very convenient to prepare trainings: problems have expected complexity and topics, there are Russian and English statements, you can see the analysis and many solutions. Because of hacks and uphacks, problems in the archive usually have strong tests. Almost all of them are well-prepared. In addition, with the help of <a href="https://mirror.codeforces.com/blog/entry/21912">user lists</a>, you can easily pick up problems for a group of students that they did not solve. <img src="/predownloaded/2f/ec/2fecbf1f7e7a8f8655f0f74576fd1f6dbbc2307...

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In Problems Statements, Examples Are Now Highlighted if Test Cases Are Used Hi, Codeforces! Remember this post https://mirror.codeforces.com/blog/entry/105779 about highlighting test cases in example inputs? Well, with a quick push, [user:Vladosiya,2025-09-17] and I have now added support for highlighting cases in the outputs as well. On hover (or tap on mobile), the corresponding input and output cases even get highlighted together. Look at this beauty: <br/> <center><img style="width:400px;" src="/predownloaded/19/5d/195dad651fa30037704e3ca2e482293210658c23.png"/></center> <br/> There's still a bit of polishing needed for situations when authors add custom outputs or in some other unusual scenarios, but the basic functionality is already there and ready to use. Enjoy the upcoming rounds!

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Codeforces Round #589 (Div. 2) **다시 만나서 반가워요, 코드포스!** (Nice to see you again, Codeforces!) I'm again happy to introduce you to [Codeforces Round #589 (Div. 2)](https://mirror.codeforces.com/contests/1228). Please look at following information for details: - This contest will take place on [contest_time:1228]. - The round will be **rated for all Division 2 participants**. - There are **6 problems** and you will have **2 hours** to solve them. Score distribution will be announced later. The listed handles below are contributors. Thank you for all who listed! - **Main author**: ~McDic,2019-09-26 &mdash; I made and prepared all problems. - **Coordinator**: ~arsijo,2019-09-26 &mdash; He is my coordinator again. - **Early phase testers**: ~dorijanlendvaj,2019-09-26 ~tfg,2019-09-26 ~Lawali,2019-09-26 &mdash; They are early phase testers. They mostly focused on test data. - **Late phase testers**: ~_Kuroni_,2019-09-26 ~imbr92,2019-09-26 ~Redux,2019-09-26 ~Dr_Park,2019-09-26 ~Mahotsukai,2019-09-26 ~TOPWINDFLOWER,20...

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Problem Ratings are Recalculated [May, 2020] Hi! As many have noticed, sometimes problem ratings were assigned in a strange way that was not consistent with expectations. For example, ratings for complex problems of Div3 rounds were often overestimated. This was mainly due to the fact that high-ranking unofficial participants did not try such problems. It turned out that despite the high rating of a participant, a problem is not solved by the participant, and this fact raised the rating of the problem. It is not entirely correct to take into account only official participants since ratings for difficult problems are sometimes more accurately determined by unofficial participants. Somewhere in the comments, I've read that problem ratings are set manually. Of course, this is not so. The process is automated, but I start it manually (I will fix it somehow). I changed the formulas for calculating problem ratings, now they slightly better correspond to expectations. New problem ratings are already available on the website. I ...

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Goodbye, 2025. Hello, 2026! <img src="/predownloaded/f4/1f/f41ff0beb745fb2f84a55d9f2cc451273efc6267.jpg" style="width:300px; float:right; margin: 0 1em 1em 1em"/> Goodbye, 2025. Hello, 2026! Dear Santa, Please make 2026 a happy year—not just for me, but for everyone. We all need this. Hello, 2026! And of course, we have our traditional gifts! #### <img src="https://assets.codeforces.com/images/wand.png"/> Change Handle Feature Hurry! Until January 10, you can change your handle (<b>but only once</b>)! Note that next time you will be able to roll back the change or request another handle change only _after a year (in December 2026)_. Choose wisely! You can change your handle to a new one that hasn't been used by anyone else, or to one that you've previously used. Links to your old profile will automatically redirect to your updated profile. Again this year, if you've participated in at least 10 rounds, you can request the handle of an _inactive_ participant. This means the participant...

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Goodbye, 2024. Hello, 2025! <img src="/predownloaded/85/58/8558df7ac8a1c33d501ea8fd9b18dd3d95886b90.png" style="width:290px; float:right; margin: 0 1.5em 1.5em 1.5em"/> Goodbye, 2024. Hello, 2025! Dear Santa Claus, Please make 2025 a happy year—not just for me, but for everyone. We all need this. Hello, 2025! And of course, we have our traditional gifts! #### <img src="https://assets.codeforces.com/images/wand.png"/> Change Handle Feature Hurry! Until the 10th of January, you can change your handle (<b>but only once</b>)! Note that you can roll back the changes or request another handle change only _after a year_. Choose wisely! You can change your handle to a new one that hasn’t been used by anyone else, or to one that you’ve previously used. Links to your old profile will automatically redirect to your updated profile. Again this year, if you’ve participated in at least 10 rounds, you can request the handle of an _inactive_ participant. This means the participant must have had a perio...

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Codeforces Round 923 (Div. 3) Gamarjoba, Codeforces! On [contest_time:1927] will start [contest:1927], the next Codeforces round for the Div.3. Lately, I've been coming up with problem ideas less frequently, but I don't want to lose this skill. Welcome to the round where all problems are my own creation! I hope you'll enjoy them. A huge thank you to [user:Vladosiya,2024-02-05] for preparing the majority of problems in Polygon. Also, thanks to [user:pashka,2024-02-05] and [user:KAN,2024-02-06] for helping with the discussion of problem ideas. Thank you very much [user:74TrAkToR,2024-02-05], [user:CLown1331,2024-02-05], [user:EternalAlexander,2024-02-05], [user:Jostic11,2024-02-05], [user:Killever,2024-02-05], [user:KoT_OsKaR,2024-02-05], [user:LoveWX,2024-02-05], [user:MADE_IN_HEAVEN,2024-02-05], [user:dan_dolmatov,2024-02-05], [user:jnmtz111__,2024-02-05], [user:pedrolino,2024-02-05], [user:theRealChainman,2024-02-05], [user:yorky,2024-02-05] for testing the round. As usual for the Div.3 rounds: ...

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Codeforces: summing up 2016 year <center> <img src="http://assets.codeforces.com/images/Happy-New-Year-HD-Wallpapers.jpg"/> </center> Somehow it turns out that for me, each coming the New Year means more and more. This is an excellent opportunity to take stock, to breathe fresh air and to go through a kind of catharsis. This is a rare opportunity to be with the family, dress up in Santa Claus and just have fun. Holidays give me a clear criterion that I do the right things. If during the holidays, I begin to think about it, to recall some deferred ideas, eager to implement something new. So I’m doing right things. My things. And now exactly the same as in several recent years: during New Year holidays I write code for Codeforces, trying new technology or simply I’m making minor changes in testlib. It is necessary to me: at this moment are no deadlines, do not press the obligation. Just now, at 3 am, I can not break away from being able to do something new. I would like to take a moment and realize that spun in ...

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