Codeforces Round #162  Hello! I'm Squirrel Liss. I became the hero of today's contest. The writers of the contest are [user:snuke,2013-01-20], [user:hogloid,2013-01-20], [user:DEGwer,2013-01-20], and [user:rng_58,2013-01-20]. I'd like to thank [user:Gerald,2013-01-20] for helping preparation, [user:Delinur,2013-01-20] for translation, and [user:MikeMirzayanov,2013-01-20] for the Codeforces system. The point values will be standard: 500-1000-1500-2000-2500 for both divisions. I will encounter many difficulties about stones, nuts, and sequences... Please help me! --- Since 07:30 PM MSK is late here, the contest will be moved to 05:00 PM MSK. Please check the schedule in your time zone in timeanddate.com: http://timeanddate.com/worldclock/fixedtime.html?iso=20130120T22&p1=248&ah=2 UPD: Announced the detail of the contest. The top five contestants in div1 were: - 1: [user:Petr,2013-01-20] - 2: [user:AleX,2013-01-20] - 3: [user...

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AtCoder Grand Contest 055 Announcement I am glad to invite you to [AtCoder Grand Contest 055](https://atcoder.jp/contests/agc055). This contest counts for GP30 scores. <ul> <li> Contest URL: <a href="https://atcoder.jp/contests/agc055">https://atcoder.jp/contests/agc055</a> </li> <li> Start time: <a href="https://www.timeanddate.com/worldclock/fixedtime.html?msg=AtCoder+Grand+Contest+055&iso=20211031T21&p1=248&ah=3">Sunday, October 31, 12:00 UTC</a> </li> <li> Duration: 180 minutes </li> <li> Number of Tasks: 6 </li> <li> Writer: [user:antontrygubO_o,2021-10-28] </li> <li> Rated range: 1200+ </li> </ul> The point values will be **400** &mdash; **700** &mdash; **900** &mdash; **1200** &mdash; **1500** &mdash; **1800** I would like to thank: <ul> <li> [user:maroonrk,2021-10-28] for an amazing coordination of this round, and for allowing me to host a contest on AtCoder for the second time </li> <li> [user:AmShZ,2021-10-28] and [user:maroonrk,2021-10-28] for a few great suggestions to improve some ...

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Code Festival 2016: New Onsite Contest with Free Trip for Finalists! We announce a new international onsite competition: Code Festival 2016. The contests will be held on [AtCoder](http://atcoder.jp). The top 20 foreign (non-Japanese) university students are invited to the Finals in Japan. (Even if you are not a student, you can participate in qualification rounds and parallel rounds of onsite contests. All of these contests are rated.) The flight tickets and hotels for finalists are paid by organizers. There will be three qualification rounds. Top 10 foreign students from round A and top 5 each from round B and C will qualify for the onsite contest. - [Round A: September 24th, 21:00 JST](http://www.timeanddate.com/worldclock/fixedtime.html?iso=20160924T2100&p1=248). - [Round B: October 10th, 13:00 JST](http://www.timeanddate.com/worldclock/fixedtime.html?iso=20161010T1300&p1=248). - [Round C: October 23rd, 21:00 JST](http://www.timeanddate.com/worldclock/fixedtime.html?iso=20161023T2100&p1=248). - Onsite Round: November 26th-28th Als...

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Educational Codeforces Round 48 [Rated for Div. 2] On [contest_time:1016] Educational Codeforces Round 48 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 extented ACM ICPC rules. 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 **7 problems** and **2 hours** to solve them. The problems were invented and prepared by Ivan [user:BledDest,2018-08-02] Androsov, Roman [user:Ajosteen,2018-08-02] Glazov, Adilbek [user:adedalic,2018-08-02] Dalabaev, Vladimir [user:Vovuh,2018-08-02] Petrov and me. Good luck to all participants! Congratulations to th...

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Codeforces Round #248 Editorial If you have any questions or suggestions, or if you have a solution different to ours that you want to share with us, feel free to comment below :) **Author solutions are added.** --- ###[Div. 2 A &mdash; Kitahara Haruki's Gift](http://mirror.codeforces.com/contest/433/problem/A) Denote $G$ as the sum of the weight of the apples. If $G/100$ is not an even number, then the answer is obviously "NO". Otherwise, we need to check if there is a way of choosing apples, so that the sum of the weight of the chosen apples is exactly $\frac{G}{2}$. A simple $O(n)$ approach would be to enumerate how many 200-gram apples do we choose, and check if we can fill the rest with 100-gram apples. We can also solve this problem using a classic knapsack DP. **Solution:** [submission:6712942] --- ###[Div. 2 B &mdash; Kuriyama Mirai's Stones](http://mirror.codeforces.com/contest/433/problem/B) Sort sequence $v$ to obtain sequence $u$. Sorting can be done in $O(n\log n)$ using quicksort. Now we ar...

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Codeforces Round #248 Statistics [contest:434] and [contest:433] round statistics [cut] : ### Div. 1 #### First accepted: **A** (00:07) [user:Coder,2014-05-23] [user:mmaxio,2014-05-23] <br/> **B** (00:25) [user:RAVEman,2014-05-23] <br/> **C** (00:39) [user:daizhenyang,2014-05-23] <br/> **D** (01:32) [user:WJMZBMR,2014-05-23] <br/> #### Total hack attempts: +179:-71 #### Top-6 hackers: **1150** [user:MrDindows,2014-05-23] +12:-1 <br/> **1100** [user:Seyaua,2014-05-23] +13:-4 <br/> **1000** [user:qazwsxedcrfvtg14,2014-05-23] +10:-0 <br/> **1000** [user:fixme,2014-05-23] +10:-0 <br/> **900** [user:evader,2014-05-23] +9:-0 <br/> **900** [user:WanderingID,2014-05-23] +9:-0 <br/> #### Other info <br/> [Complete Results](https://lh4.googleusercontent.com/-LirEeqqu7sU/U4CKrvohmZI/AAAAAAAAB5A/Mj3Gy3yKUAA/s0/CF_248_1_2.png)<br/><br/> ![ ](https://lh4.googleusercontent.com/-Fw5Q9GcYerg/U4CKrmzVrWI/...

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Codeforces Round #248 Hello everybody! We invite you to participate in Codeforces Round #248, which will take place at [11:00AM MSK on Saturday, May 24th](http://www.timeanddate.com/worldclock/fixedtime.html?msg=Codeforces+Round+%23248&iso=20140524T11&p1=166&ah=2). This round will be held in both divisions. Note that the starting time of this round is quite unusual. The problems were prepared by [user:zhonghaoxi,2014-05-22], [user:wyx528,2014-05-22] and me. This is our first Codeforces round and we hope it will be a good one. Many thanks to [user:Gerald,2014-05-22], who gave us enormous help during the preparations for this round; to [user:colin,2014-05-22] and [user:MSTyoda,2014-05-22], who are the testers of this round; and to [user:MikeMirzayanov,2014-05-22], who created such a wonderful platform. In Div. 1, scores for each problem will be **500-1000-1500-2000-3000**. In Div. 2, scores for each problem will be **500-1500-1500-2000-2500**. Hope you enjoy the problems! Good luck and have fun...

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CODE FESTIVAL 2016 Qualification Round B [CODE FESTIVAL 2016 Qualification Round B](http://atcoder.jp/) will be held on Monday [(time)](http://www.timeanddate.com/worldclock/fixedtime.html?iso=20161010T1300&p1=248). The writer is [user:DEGwer,2016-10-08]. [Contest Link](https://code-festival-2016-qualb.contest.atcoder.jp/) [Contest Announcement](https://atcoder.jp/) This is one of the three qualification rounds of CODE FESTIVAL. Top 5 foreign students of this round will qualify. If you are eligible for the onsite contest, please don't forget to fill the form at https://krs.bz/rhd-itm/m/code_fes_2016. Please check the detail of the tournament at http://mirror.codeforces.com/blog/entry/46647. The contest duration is 2 hours, and there will be 5 problems. The first 4 problems are mainly used for choosing domestic students and much easier than other tournament competitions. However, we added one more problem and we hope this is interesting enough for choosing top 5 qualifiers. (Anyway, most probably the qualifiers will be de...

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AtCoder Grand Contest 052 Announcement I am glad to invite you to [AtCoder Grand Contest 052](https://atcoder.jp/contests/agc052). This contest counts for GP30 scores. <ul> <li> Contest URL: <a href="https://atcoder.jp/contests/agc052">https://atcoder.jp/contests/agc052</a> </li> <li> Start time: <a href="https://www.timeanddate.com/worldclock/fixedtime.html?iso=20210307T2100&p1=248">Sunday, March 7, 12:00 UTC</a> </li> <li> Duration: 160 minutes </li> <li> Number of Tasks: 6 </li> <li> Writer: [user:antontrygubO_o,2021-03-03] </li> <li> Rated range: 1200+ </li> </ul> I would like to thank: <ul> <li> [user:maroonrk,2021-03-03] for allowing me to host a contest on AtCoder and for the great coordination of this round </li> <li> [user:kefaa2,2021-03-03], [user:gamegame,2021-03-03], [user:TheOneYouWant,2021-03-03], [user:hugopm,2021-03-03], [user:HIR180,2021-03-03] for testing this round </li> <li> [user:MikeMirzayanov,2021-03-03] for the great Polygon platform (only Polygon this time) </li> </ul...

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Educational Codeforces Round 44 [Rated for Div. 2] Hello Codeforces! On [contest_time:985] Educational Codeforces Round 44 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 extented ACM ICPC rules. After the end of the contest you will have one day to hack any solution you want. You will have access to copy any solution and test it locally. You will be given **7 problems** and **2 hours** to solve them. The problems were prepared by Adilbek [user:adedalic,2018-05-20] Dalabaev, Vladimir [user:Vovuh,2018-05-20] Petrov and me. Good luck to all participants! Congratulations to the winners: <table class='bordertable'> <tbody> <tr> <th>Rank</th> ...

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【LGR-248】Luogu Round 248 Announcement We will hold Luogu Round 248 on Luogu. This is a Div.1/2 round. English statement will be provided officially. You can click the button to change language.  - Contest URL: - Div.1: <https://www.luogu.com.cn/contest/230986> - Div.2: <https://www.luogu.com.cn/contest/276844> - Start Time: [11.09 14:00(UTC+8)](https://www.timeanddate.com/worldclock/fixedtime.html?iso=20251109T1400&p1=237) - Duration: 240 minutes - System: IOI - Difficulty: similar to CF Div.1/2 - Coordinator: [user:E.Space,2025-11-08], [user:emptyhope,2025-11-08] - Staffs: [user:ma2021tyoi0037,2025-11-08], [user:ty_ak,2025-11-08], [user:wangmarui,2025-11-08], [user:not_clever_sylCF,2025-11-08], [user:hzy_mod,2025-11-08] - Rated range: Div.1 unlimited; Div.2 <=2000 rating on Luogu - Score distribution: 100-100-100-100 for each division We are looking forward to...

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Codeforces Beta Round #86 Разбор <p></p><div><b>Div 2. Задача А.</b>&nbsp;<span class="Apple-style-span" style="font-family: verdana, arial, sans-serif; font-size: 13px; background-color: rgb(248, 248, 248); "><a href="http://mirror.codeforces.com/contest/114/problem/A" style="color: rgb(0, 0, 204); ">Cifera</a></span><br></div><div>Если переформулировать задачу то необходимо было определить&nbsp;является ли число l, некоторой положительной степенью числа &nbsp;$k$. Для этого можно делать одно из двух:</div><div>1) В 64-битном типе данных найти минимальную степень $h$ числа $k$, такую что $k^h \ge l$. Если $k^h = l$, то ответ&nbsp;$YES$, и число артиклей - $h-1$, иначе $NO$.</div><div>2) Будем делить $l$ на&nbsp;$k$, пока&nbsp;$l$ делится на&nbsp;$k$ и $l \ne 1$. Если $l = 1$, то ответ - $YES$ и число делений-1, иначе ответ $NO$.</div><div><br></div><div><b>Div 2. Задача B.</b>&nbsp;<span class="Apple-style-span" style="font-family: verdana, arial, sans-serif; font-size: 13px; background-color: rgb(255, 255, 255); "><a href="...

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Codeforces Round #570 (Div. 3) &lt;almost-copy-pasted-part&gt; Hello! [contest:1183] will start at [contest_time:1183]. You will be offered 6 or 7 problems (or 8) 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 rating 1600 or higher, can register for the round unofficially. The round will be hosted by rules of educational rounds (extended ACM-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. I tried to make strong tests &mdash; just like you will be upset if many solutions fail after the contest is over. You will be given 6 or 7 (or 8) problems and 2 hours to solve them. Note that **the penalty** for the wrong submission in this round (and the following Div. 3 rounds) is **10 minutes**. [Remember] (/blog/entry/59228) that only the <i>trusted participants of the third division</i> will be included in the ...

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Educational Codeforces Round 46 [Rated for Div. 2] Hello, Codeforces! On [June 27, 17:35 MSK](https://www.timeanddate.com/worldclock/fixedtime.html?day=27&month=6&year=2018&hour=17&min=35&sec=0&p1=166) Educational Codeforces Round 46 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>. As usual, the round will be **rated for the participants with rating lower than 2100**. It will be held on extented ACM ICPC rules. 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 **7 problems** and **2 hours** to solve them. The problems were prepared by Adilbek [user:adedalic,2018-06-26] Dalabaev, Roman [user:Ajosteen,2018-06-26] Glazov, Mikhail [user:PikMik...

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CODE FESTIVAL 2016 Qualification Round A [CODE FESTIVAL 2016 Qualification Round A](http://atcoder.jp/) will be held on Saturday [(time)](http://www.timeanddate.com/worldclock/fixedtime.html?iso=20160924T2100&p1=248). The writer is [user:sugim48,2016-09-23]. [Contest Link](https://code-festival-2016-quala.contest.atcoder.jp/) [Contest Announcement](https://atcoder.jp/) This is one of the three qualification rounds of CODE FESTIVAL. Top 10 foreign students of this round will qualify. If you are eligible for the onsite contest, please don't forget to fill the form at https://krs.bz/rhd-itm/m/code_fes_2016. Please check the detail of the tournament at http://mirror.codeforces.com/blog/entry/46647. The contest duration is 2 hours, and there will be 5 problems. The first 4 problems are mainly used for choosing domestic students and much easier than other tournament competitions. However, we added one more problem and we hope this is interesting enough for choosing top 10 qualifiers. (Anyway, most probably the qualifiers will ...

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CODE FESTIVAL 2016 Qualification Round C [CODE FESTIVAL 2016 Qualification Round C](http://atcoder.jp/) will be held on <b><font color="red">Sunday</font></b> <s>Monday</s> [(time)](http://www.timeanddate.com/worldclock/fixedtime.html?iso=20161023T2100&p1=248). The writer is [user:sigma425,2016-10-21]. [Contest Link](https://code-festival-2016-qualc.contest.atcoder.jp/) [Contest Announcement](https://atcoder.jp/) This is one of the three qualification rounds of CODE FESTIVAL. Top 5 foreign students of this round will qualify. If you are eligible for the onsite contest, please don't forget to fill the form at https://krs.bz/rhd-itm/m/code_fes_2016. Please check the detail of the tournament at http://mirror.codeforces.com/blog/entry/46647. The contest duration is 2 hours, and there will be 5 problems. The first 4 problems are mainly used for choosing domestic students and much easier than other tournament competitions. However, we added one more problem and we hope this is interesting enough for choosing top 5 qualifiers. ...

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CODE FESTIVAL 2017 Qualification Round C [CODE FESTIVAL 2017 Qualification Round C](https://www.recruit-jinji.jp/recruitment/code_fes/us/index.html) will be held on Sunday [(time)](http://www.timeanddate.com/worldclock/fixedtime.html?iso=20171022T2100&p1=248). The writers are [user:sugim48,2017-10-19] and [user:wo_,2017-10-19]. [Contest Link](https://code-festival-2017-qualc.contest.atcoder.jp/) Contest Announcement will be posted later. This is one of the three qualification rounds of CODE FESTIVAL. In total, 20 foreign students will qualify in three rounds (Check [the official site](https://www.recruit-jinji.jp/recruitment/code_fes/us/index.html) for detailed rules). <b><font color="red">If you are eligible for the onsite contest, please don't forget to fill the form at https://krs.bz/rhd-itm/m/codefes2017_en.</font></b> Please check the detail of the tournament at http://mirror.codeforces.com/blog/entry/53502. The contest duration is 2 hours, and there will be 6 problems. The first 4 problems are mainly used for choos...

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CODE FESTIVAL 2017 Qualification Round A [CODE FESTIVAL 2017 Qualification Round A](https://www.recruit-jinji.jp/recruitment/code_fes/us/index.html) will be held on Saturday [(time)](http://www.timeanddate.com/worldclock/fixedtime.html?iso=20170923T2100&p1=248). The writer is [user:sugim48,2017-09-22] and [user:DEGwer,2017-09-22]. [Contest Link](https://code-festival-2017-quala.contest.atcoder.jp/) [Contest Announcement](https://atcoder.jp/post/149) This is one of the three qualification rounds of CODE FESTIVAL. In total, 20 foreign students will qualify in three rounds (Check [the official site](https://www.recruit-jinji.jp/recruitment/code_fes/us/index.html) for detailed rules). <b><font color="red">If you are eligible for the onsite contest, please don't forget to fill the form at https://krs.bz/rhd-itm/m/codefes2017_en.</font></b> Please check the detail of the tournament at http://mirror.codeforces.com/blog/entry/53502. The contest duration is 2 hours, and there will be 6 problems. The first 4 problems are mainly us...

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Educational Codeforces Round 87 [Rated for Div. 2] Hello Codeforces! On [contest_time:1354] [contest:1354] will start. **Please notice the unusual time.** 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 Roman [user:Roms,2020-05-15] Glazov, Adilbek [user:adedalic,2020-05-15] Dalabaev, Vladimir [...

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CODE FESTIVAL 2017 Qualification Round B [CODE FESTIVAL 2017 Qualification Round B](https://www.recruit-jinji.jp/recruitment/code_fes/us/index.html) will be held on Sunday [(time)](http://www.timeanddate.com/worldclock/fixedtime.html?iso=20171008T2100&p1=248). The writers are [maroonrk](https://atcoder.jp/user/maroonrk), [user:snuke,2017-10-07], and myself. [Contest Link](https://code-festival-2017-qualb.contest.atcoder.jp/) [Contest Announcement](https://atcoder.jp/post/155) This is one of the three qualification rounds of CODE FESTIVAL. In total, 20 foreign students will qualify in three rounds (Check [the official site](https://www.recruit-jinji.jp/recruitment/code_fes/us/index.html) for detailed rules). <b><font color="red">If you are eligible for the onsite contest, please don't forget to fill the form at https://krs.bz/rhd-itm/m/codefes2017_en.</font></b> Please check the detail of the tournament at http://mirror.codeforces.com/blog/entry/53502. The contest duration is 2 hours, and there will be 6 problems. The fir...

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Contests hack statistics (Number of hacks by round) Just felt like gathering some data about hacks. Parsed around ~400 last contests Probably it would be worth it to also include SFT, but whatever Educational 96 is not finished yet but also whatever Last 100 ------------------ **847** Educational Codeforces Round 96 (Rated for Div. 2) **30** Codeforces Global Round 11 **248** Codeforces Round #674 (Div. 3) **0** 2020 ICPC, COMPFEST 12, Indonesia Multi-Provincial Contest (Unrated, Online Mirror, ICPC Rules, Teams Preferred) **97** Bubble Cup 13 &mdash; Finals [Online Mirror, unrated, Div. 2] **86** Bubble Cup 13 &mdash; Finals [Online Mirror, unrated, Div. 1] **20** Codeforces Round #675 (Div. 2) **1** Codeforces Round #672 (Div. 2) **70** Codeforces Round #671 (Div. 2) **58** Educational Codeforces Round 95 (Rated for Div. 2) **3** Codeforces Round #673 (Div. 2) **11** Codeforces Round #673 (Div. 1) **73** Codeforces Round #667 (Div. 3) **121** Grakn Forces 2020 **4** Co...

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Round #9 contest analysis and winners Hello Codeforces! The latest [csacademy](https://csacademy.com/) contest, [Round #9](https://csacademy.com/contest/round-9/) took place on Tuesday, July/26/2016. First of all congratulations to the winners: 1. [user:FatalEagle,2016-07-28] 1. [user:uwi,2016-07-28] 1. [user:anta,2016-07-28] 1. [user:tourist,2016-07-28] 1. [user:I_Love_Tanya_Romanova,2016-07-28] In addition to the top 5 finishers, we initially announced that we're going to have 2 more special prizes. Meanwhile we changed our mind and decided to have **3** special prizes: 1. The first special prize is awarded to [user:snuke,2016-07-28], for being the first one to solve [Sum of Squares](https://csacademy.com/contest/round-9/#task/sum-of-squares), which proved to be the second hardest problem after [Jetpack](https://csacademy.com/contest/round-9/#task/jetpack). 1. The second special prize is awarded to [user:Kostroma,2016-07-28] for a correct solution at [Jetpack](https://csacademy.com/contest/round-9/#task/...

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TCO15 round 2C This year's TopCoder Open includes, in addition to onsite final round, four onsite events, which take place in various cities around the globe simultaneously with the sub-rounds of round 2. As a result, the times for these rounds become known later than usual. The times for rounds [2A](/blog/entry/17471), [2B and 2D](/blog/entry/18104) have already been announced, and now the time for round 2C is announced as well. Round 2C will take place on July 18th in Tokyo, at the office of [Dwango Co.](http://info.dwango.co.jp/english/)  Like on the other onsite events, there will be a [hackathon](http://hackathons.topcoder.com/tco15-japan) and t-shirts. Unlike the other onsite events, there will be round 2 explanation by [user:iwiwi,2015-06-08] and [user:rng_58,2015-06-08]. The event will begin at [11:00 AM](http://www.timeanddate.com/worldclock/fixedtime.html?msg=TCO15+Japan+Event&...

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Upcoming AtCoder Contests We will not hold AtCoder Regular Contests for a while. Probably the next ARC will be in March. Instead, there will be several sponsored tournaments. The onsite rounds of these tournaments are only for Japanese (we are sorry for that), but we will try to translate majority of qualification rounds into English. In case the problems are translated, usually the contest is rated for <2800 (there can be exceptions, so please check individual announcements). The difficulty/quality of those rounds are at the same level as usual ARCs &mdash; so please participate in those contests! There will be one such contest this Saturday (20:00 JST, an hour earlier than usual), and I think it will be announced soon. There will be two more AGCs this year. [date/time of AGC029](https://www.timeanddate.com/worldclock/fixedtime.html?iso=20181215T2100&p1=248) [date/time of AGC030](https://www.timeanddate.com/worldclock/fixedtime.html?iso=20181229T2100&p1=248) After these AGCs, we will announce the to...

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Codeforces Beta Round #87 <p></p><div>Welcome to&nbsp;<b>Codeforces Beta Round #87</b>!</div><div><br></div><div><span class="Apple-style-span">The mysterious author of today's match (which turns out to be me) have prepared seven problems for you (five in each division). Since I can't spoil you any of the problems yet, for now I can safely say that I like all of today's problems. The problem statements are wonderfully crafted (and translated) with the help of both&nbsp;</span><span class="Apple-style-span" style="font-family: verdana, arial, sans-serif; font-size: 12px; line-height: 20px; background-color: rgb(255, 255, 255); "><a class="rated-user user-admin" href="http://mirror.codeforces.com/profile/RAD" title="Штаб, RAD" style="font-family: arial; text-decoration: none !important; font-weight: bold; color: rgb(0, 0, 204); ">RAD</a></span><span class="Apple-style-span">&nbsp;and</span><span class="Apple-style-span" style="font-family: verdana, arial, sans-serif; font-size: 12px; line-height: 20px; background-color:...

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AtCoder Beginner Contest 100 Hello everybody!<br /> <br /> I'm delighted to invite you to anniversary round [AtCoder Beginner Contest 100](https://abc100.contest.atcoder.jp/), which starts at [Saturday, June 16, 2018 at 21:00 JST](https://www.timeanddate.com/worldclock/fixedtime.html?iso=20180616T2100&p1=248). The time is as usual as previous round. (However, some of AtCoder contest start time is unusual...)<br /> <br /> This is the fifth round for a Japanese twin-brothers: [user:E869120,2018-06-13] and [user:square1001,2018-06-13]. I already held AtCoder Beginner Contest 064, 076, 088, 096, and this time, it's 100. Multiple-of-four again, again and again! (Where is the probability 1/1024 ???) Anyway, ultimate thanks for [user:rng_58,2018-06-13] for reviewed and refined my problems, [user:chokudai,2018-06-13] for creating one of the best contest platform in the universe. It is obvious that I could not be able to host the contest without cooperation of these two people.<br /> <br /> The round is **rated** for...

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AtCoder Petrozavodsk Contest 001 We've just rescheduled our contests. Next Saturday, we'll hold a long (most probably 5 hours, but it is not finalized yet) contest on AtCoder. Note that the start time is unusual: please check [here](https://www.timeanddate.com/worldclock/fixedtime.html?iso=20180203T2300&p1=248). The problems are based on one of the problemsets of Petrozavodsk camp. If you are a participant of Petrozavodsk camp, please don't participate in this contest. And of course, please keep the problems secret! This is a **rated** contest for everyone, and this contest **counts for GP30 scores**. If you are a Petrozavodsk participant and you care GP30 scores, please let me know. We'll make sure that you won't get disadvantages (please check [here](https://atcoder.jp/post/171), we'll handle you as a writer, i.e., increase the value of Y by one). The writers are japan02 team ([user:yosupo,2018-01-28], [user:sugim48,2018-01-28], [user:sigma425,2018-01-28]). Note that AGC 021 was postponed to avoid col...

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Educational Codeforces Round 34 [Rated for Div. 2] Hello Codeforces! On [December 12, 18:05 MSK](https://www.timeanddate.com/worldclock/fixedtime.html?day=12&month=12&year=2017&hour=18&min=5&sec=0&p1=166) Educational Codeforces Round 34 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 Div. 2** again. It will be held on extented ACM ICPC rules. After the end of the contest you will have one day to hack any solution you want. You will have access to copy any solution and test it locally. You will be given **7 problems** and **2 hours** to solve them. The problems were prepared by Mikhail [user:PikMike,2017-11-08] Piklyaev, Ivan [user:BledDest,2017-11-22] Androsov and me. Good luck to all participants! I also have a ...

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Codeforces Beta Round #61 (Div. 2) <font class="Apple-style-span" face="verdana, arial, sans-serif"><table class="standings" style="border-collapse: collapse; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; width: 1168px; font-size: 14px; "><tbody><tr><th class="top left" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0.5em; padding-right: 0.5em; padding-bottom: 0.5em; padding-left: 0.5em; font-style: normal; font-weight: bold; text-align: center; border-top-width: initial; border-top-style: none; border-top-color: initial; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(225, 225, 225); font-size: 0.9em; border-left-style: none; border-left-width: initial; border-left-color: initial; width: 2em; ">#</th><th class="top" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0.5em; padding-right: 0.5em; padding-bottom: 0.5em; padding-left: 0.5em; font-style: normal; font-weight: b...

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square869120Contest #6 in AtCoder! Hello, Codeforces!<br /> <br /> Finally, the season of square869120Contest comes. I am filled with deep emotion when I think of the dawn of this contest :)<br /> <br /> On [April 14th, 20:00 JST](https://www.timeanddate.com/worldclock/fixedtime.html?iso=20190414T2000&p1=248), an innovative contest, [square869120Contest #6](https://atcoder.jp/contests/s8pc-6) will be held. As usual, I'll invite everyone includes non-Japanese participants, and in previous contest, 20 non-Japanese participants joined in the contest. Hope in this year, much more will join :)<br /> <br /> square869120Contest is a competition which is held by a twins: [user:E869120,2019-04-09] and [user:square1001,2019-04-09]. This round is our sixth voluntary contest, counting from from our first round when we were 7-th grader. Now we are 11-th grader, but we are making much efforts to achieve continuous-growing of the contest, including some experience of writing problems of AtCoder Beginner Contests and others.<br /...

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Codeforces Global Rounds 2020: Final Results In 2020, with the support of XTX Markets, 6 rounds of the Codeforces Global Rounds were held. Each round was common for both divisions. All such rounds were rated for all participants. At each such round, 50 brand T-shirts were handed out, and we gave T-shirts to all problem writers! I say a big thank you to XTX Markets (and personally to Yuri Bedny and Alexander Gerko) for supporting Global Rounds. Without your help, we could not host them! I sincerely admire companies like these who come to support and develop the community that some of their employees come from. It will be great if other companies follow the example and also offer their help. We need it! The prizes for the 6-round series in 2020: - 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...

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Codeforces Global Rounds 2019: Final Results In 2019, with the support of XTX Markets, 6 rounds of the new Codeforces Global Rounds were held. Each round was common for both divisions and had 7–9 problems. The duration of the rounds was 2-3 hours, depending on the number and complexity of the problems. All such rounds were rated for all participants. At each such round, 50 brand T-shirts were handed out, and we gave T-shirts to all authors and problem testers as well. The prizes for the 6-round series in 2019: - 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. Final results: [cut]<br/> | Place | Contestant | = | Round 1 | Round 2| Round 3 | Round 4 | Round 5 | Round 6 | | - | - | - | - | - | - | - | - | - | | 1 | [user:tourist,2019-12-17] | <b> 2987 </b> | ...

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Toyota Programming Contest 2023 Spring Qual A（AtCoder Beginner Contest 288） Announcement We will hold Toyota Programming Contest 2023 Spring Qual A（AtCoder Beginner Contest 288）. - Contest URL: https://atcoder.jp/contests/abc288 - Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20230204T2100&p1=248 - Duration: 100 minutes - Number of Tasks: 8 - Writer: [user:leaf1415,2023-02-02], [user:cn449,2023-02-02], [user:chokudai,2023-02-02], [user:nok0,2023-02-02], [user:PCTprobability,2023-02-02], [user:m_99,2023-02-02] - Tester: kyopro_friends, [user:math957963,2023-02-02] - Rated range: ~ 1999 The point values will be 100-200-300-400-500-500-600-600. Since this contest is used as a qualification round for a local event, the style of problems is modified a bit. - Up to task C is usual. - (the style of tasks D-Ex in this contest) is between (the style of tasks D-Ex in usual ABC) and (the style of earlier tasks in usual ARC). - Tasks in the middle of this contest are slightly harder than usual. Later tasks are not too difficult. We are looki...

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Баг: номер контеста 30 июня <p><meta http-equiv="content-type" content="text/html; charset=utf-8">На странице&nbsp;<a href="http://mirror.codeforces.com/contests">http://mirror.codeforces.com/contests</a> сейчас написано:</p><p><meta http-equiv="content-type" content="text/html; charset=utf-8"><span class="Apple-style-span" style="font-family: verdana, arial, sans-serif; font-size: 14px; "></span></p><div class="datatable" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 3px; padding-left: 0px; width: 878px; position: relative; background-color: rgb(225, 225, 225); "><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 4px; padding-right: 0px; padding-bottom: 0px; padding-left: 6px; font-size: 1em; position: relative; ">Предстоящие или текущие соревнования<div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; p...

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Problem A. Codeforces Beta Round 81 <p>Hello:</p><div><br></div><div>Is the mastering in details the best way of assess a good programmer? Perhaps, but not at least in algorithm programming.&nbsp;</div><div><br></div><div>It's awful and cruel that some precision error of C or C++ led us to WA:</div><div><span class="Apple-style-span" style="font-family: verdana, arial, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255); ">9400 * 0.99 = 9306<br></span></div><div><span class="Apple-style-span" style="font-family: verdana, arial, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255); ">C, C++: (int)(9400 * 0.99) = 9305 Perhaps in other languages too.</span><br></div><div><span class="Apple-style-span" style="font-family: verdana, arial, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255); "><br></span></div><div><span class="Apple-style-span" style="font-family: verdana, arial, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255); ">High experienced programmers eventuall...

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Codeforces Global Rounds 2021: Final Results (GR13-GR18) Tomorrow will be the first global round of this year. And we are happy to sum up the results of last season. We announce the results! We remind you that the global rounds are a joint initiative of XTX and Codeforces. We are happy to announce that they continue into the new year. 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. The final standings after six rounds (sorted by total points in four best placed rounds): | Place | Contestant | = | GR 13 | GR 14 | GR 15 | GR 16 | GR 17 | GR 18| |--...

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AtCoder Grand Contest 035 Announcement We will hold AtCoder Grand Contest 035. This contest counts for GP30 scores. - Contest URL: https://atcoder.jp/contests/agc035 - Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20190714T2100&p1=248 - Duration: TBD (around 2 hours) - Number of Tasks: 6 - Writer: [user:DEGwer,2019-07-13], [user:camypaper,2019-07-13], [user:chokudai,2019-07-13] - Rated range: All The point values will be announced later. We are looking forward to your participation! <font color="red">UPD: We are very sorry, due to an urgent trouble we delay the round by 30 minutes.</font> <font color="red">UPD2: We fixed the trouble and the round will start from 21:30 JST. Again we are very sorry for the inconvenience.</font>

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Codeforces Global Rounds 2021: Current Results (GR13-GR17) In 2021 (as in 2019 and 2020), with the support of XTX Markets, 6 rounds of the new Codeforces Global Rounds are held: common rounds for both divisions of 7–9 problems each. The duration of the rounds is 2-3 hours, depending on the number and complexity of the problems. All such rounds are rated for all participants. <i>At each such round, 50 brand T-shirts are handed out, and we are happy to give T-shirts to all problem authors.</i> The prizes for the 6-round series in 2021: - 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 five rounds he placed the highest. - The best 20 participants over all series get sweatshirts and place certificates. Current standings after five rounds (sorted by total points in four best placed rounds): | Place | Contestant | = | GR 13 | GR 14 | GR 15 | GR 16 | GR 17| | - | - | - | - | - | - | - | - | | ...

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Codeforces Global Rounds 2019: Current Results After Five Rounds In 2019, with the support of XTX Markets, 6 rounds of the new Codeforces Global Rounds will be held. These will be common rounds for both divisions of 7–9 problems each. The duration of the rounds will be 2-3 hours, depending on the number and complexity of the problems. All such rounds will be rated for all participants. <i>At each such round, 50 brand T-shirts will be handed out, and we will be happy to give T-shirts to all authors and problem testers.</i> The prizes for the 6-round series in 2019: - 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. Current standings after five rounds: | Place | Contestant | = | Round 1 | Round 2| Round 3 | Round 4 | Round 5 | | - | - | - | - | - | - | - | - | | 1 | [user:tourist,201...

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Invitation to JAG Summer Camp Contest Day2 Contest Hello Codeforces! On 16th September Japan Alumni Group Summer Camp 2018 Day 2 Contest will take place on AtCoder [Contest link](https://beta.atcoder.jp/contests/jag2018summer-day2)(You cannot view contest page yet). This contest is not an official AtCoder round, so it is not rated. The contest is ICPC style practice contest, and you can take part in it as a team. But you cannot use more than one computers, browse the internet, or copy-paste your library. Since AtCoder does not support team participation, please make a new account and share it if you want to compete as a team. The problems are prepared by [user:maroonrk,2018-09-14], [user:sigma425,2018-09-14], [user:sugim48,2018-09-14], and me. Some of the problems were used in Petrozavodsk camp last winter, so if you participated in it, please refrain from competing in this contest. Note that the problems are **not** used in AtCoder Petrozavodsk Contest (see https://mirror.codeforces.com/blog/entry/57395 ). The contest starts...

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AtCoder Beginner Contest 096 Hello, Codeforces!<br /> <br /> On [May 5th, 21:00 JST](https://www.timeanddate.com/worldclock/fixedtime.html?iso=20180505T2100&p1=248), [AtCoder Beginner Contest 096](https://abc096.contest.atcoder.jp/) will be held.<br /> <br /> The problems were prepared by [user:square1001,2018-05-03] and me ([user:E869120,2018-05-03]). Thank you for [user:chokudai,2018-05-03], [user:rng_58,2018-05-03], [user:evima,2018-05-03] to helping us to host the round on AtCoder!<br /> <br /> You will be given **100 minutes** and there are **4 problems** with following scores: 100 &mdash; 200 &mdash; 300 &mdash; 400.<br /> <br /> This contest is **rated** for all participants whose rating is less than 1200, but as usual, participants whose rating is more or equal to 1200 can take part out of competition.<br /> <br /> Good luck and have fun!<br /> <br /> <h5>UPDATE</h5> <ul> <li>The contest will start in **less than a day**.</li> <li>The contest is over! Thank you for your participation! Let's ...

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Toyota Programming Contest 2023 Spring Qual B（AtCoder Beginner Contest 290） Announcement We will hold Toyota Programming Contest 2023 Spring Qual B（AtCoder Beginner Contest 290）. - Contest URL: https://atcoder.jp/contests/abc290 - Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20230219T2100&p1=248 - Duration: 100 minutes - Number of Tasks: 8 - Writer: [user:yuto1115,2023-02-19], [user:physics0523,2023-02-19], [user:PCTprobability,2023-02-19], [user:m_99,2023-02-19] - Tester: [user:m_99,2023-02-19], [user:leaf1415,2023-02-19] - Rated range: ~ 1999 The point values will be 100-200-300-400-500-500-600-600. Since this contest is used as a qualification round for a local contest, the problems are adjusted accordingly. For the style / difficulty of problems, please refer to Qual A.

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Need a help.....why runtime error (Codeforces Beta Round #50 Problem D)??? <pre class="source prettyprint" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 2px; padding-right: 2px; padding-bottom: 2px; padding-left: 2px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-top-style: solid; border-right-style: solid; border-bottom-style: solid; border-left-style: solid; border-top-color: rgb(136, 136, 136); border-right-color: rgb(136, 136, 136); border-bottom-color: rgb(136, 136, 136); border-left-color: rgb(136, 136, 136); "><font class="Apple-style-span" face="verdana, arial, sans-serif"><p class="MsoNormal" style="color: rgb(136, 0, 0); "><span style="color:black;mso-themecolor:text1">In my compiler (Code::blocks 8.02) my code runs well &amp; i got correct answer too for Test#79 but i got "RUNTIME_ERROR" when i had submitted.<o:p></o:p></span></p><p class="MsoNormal" style="color: rgb(136, 0, 0); "><span style="color:black;mso-themecolor:text1">Can anyone say...

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AtCoder Beginner Contest 076 Hello Codeforces!<br /> <br /> I'm quite excited to invite you to [AtCoder Beginner Contest 076](https://abc076.contest.atcoder.jp/) which will held on [Saturday, October 28th 21:00 JST](https://www.timeanddate.com/worldclock/fixedtime.html?iso=20171028T2100&p1=248) and lasts for 100 minutes.<br /> <br /> The round problems are created by me ([user:E869120,2017-10-27]) and [user:square1001,2017-10-27].<br /> <br /> This contest will have four problems and it is **rated** for contestants whose rating is below 1200. The same as before, contestants whose rating is more than or equal to 1200 can take part out of competition.<br /> <br /> The scoring is: 100 &mdash; 200 &mdash; 300 &mdash; 400.<br /> <br /> I hope you can have fun during the contest. Good luck and have fun, wish you high rating!<br /> <br /> See you tomorrow!<br /> <br /> <br /> UPD 1: The editorial is [here](https://img.atcoder.jp/abc076/editorial.pdf). Thank you for participating!<br /> <br /> **UPD 2: Co...

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The 16th Japanese Olympiad in Informatics Final Round Online Contest Hello Codeforces! [The 16th Japanese Olympiad in Informatics Final Round Online Contest](http://cms.ioi-jp.org/joi-ho-2017/index-en.html) will be held on [12 Feb. (00:30 &mdash; 04:30 GMT)](https://www.timeanddate.com/worldclock/fixedtime.html?msg=The+16th+Japanese+Olympiad+in+Informatics+Final+Round+Online+Contest&iso=20170212T0930&p1=248&ah=4). The contest duration is 4 hours and there will be 5 problems, which is the same as the 16th JOI Final Round. Problem statements will be provided both in Japanese and English this year. Details are available in [contest information](http://cms.ioi-jp.org/joi-ho-2017/index-en.html) . Good luck and have fun! UPD: Registration is available now. UPD2: Judge server is open now. You can submit your solutions. You need remake your account to use judge. UPD3: Editorial will be provided only in Japanese. Judge data and sample source codes will also be provided.

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AtCoder Regular Contest 186 Announcement We will hold AtCoder Regular Contest 186. - Contest URL: https://atcoder.jp/contests/arc186 - Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20241027T2100&p1=248 - Duration: 120 minutes - Number of Tasks: 5 - Writer: [user:nuip,2024-10-26] - Tester: [user:maroonrk,2024-10-26] - Rated range: 1200 ~ 2799 The point values will be <s>800-900-900-900-1000</s> <font color="red">900-900-900-900-1000</font>. Note: This ARC also serves as a qualification round to select the 18 contestants for the Japanese national finals, making it significantly more difficult than a regular ARC. <s>(For reference, the difficulty is close to that of ARC184.)</s> <font color="red">Due to circumstances, we replaced the tasks and changed the point values. Since there are no easy tasks, the difficulty level of solving one or more tasks has increased. Please be careful. Since the difficulty level is flat, we recommend reading all the tasks and not necessarily solving them in o...

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AtCoder Beginner Contest 262 Announcement We will hold AtCoder Beginner Contest 262. - Contest URL: https://atcoder.jp/contests/abc262 - Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20220731T2100&p1=248 - Duration: 100 minutes - Number of Tasks: 8 - Writer: [user:m_99,2022-07-30], [user:KoDaman,2022-07-30], kyopro_friends, [user:leaf1415,2022-07-30], [user:PCTprobability,2022-07-30], [user:nok0,2022-07-30] - Tester: [user:PCTprobability,2022-07-30], [user:physics0523,2022-07-30] - Rated range: ~ 1999 The point values will be 100-200-300-400-500-500-600-600. Since this is used as a qualification round of a local contest, - Earlier problems are easy to implement. - Later problems have similar difficulties. - The style of problems are slightly different (though closer to normal ABCs than to normal ARCs). We are looking forward to your participation!

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TLE for Problem B in Round #248 — Div 2 Dear all, In Round #248 &mdash; Div 2, Problem B &mdash; Kuriyama Mirai's Stones ([problem:433B]) I submitted a solution for Problem B ([submission:6697154]) It failed during the system test (Time limit exceeded on test 46) I am wondering why. My solution passed tests 42, 43 and 45 which contains the maximum allowed input in about 343 ms. How it failed and gave TLE (2000 ms) with case 46 which is simpler than the above cases. If there was an error in the system, how can I contact the responsible to solve this problem? Thanks in advance.

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AtCoder Regular Contest 201 Announcement We will hold AtCoder Regular Contest 201. - Contest URL: https://atcoder.jp/contests/arc201 - Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20250622T2100&p1=248 - Duration: 120 minutes - Number of Tasks: 6 - Writer: [user:snuke,2025-06-19] - Tester: [user:Nyaan,2025-06-19], [user:maspy,2025-06-19] - Rated range: 1200 ~ 2799 The point values will be 500-500-600-700-800-1000. Please note that the rated range differs from usual, as this ARC also serves as a qualifying round for a domestic contest in Japan. We are looking forward to your participation!

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AtCoder Beginner Contest 088 Hello Codeforces!<br /> <br /> On [February 18th, 21:00 JST](https://www.timeanddate.com/worldclock/fixedtime.html?iso=20180218T2100&p1=248), [AtCoder Beginner Contest 088](https://abc088.contest.atcoder.jp/) will start.<br /> <br /> [Announcement Page](http://atcoder.jp/post/199)<br /> <br /> The problems were prepared by [user:square1001,2018-02-17] and me ([user:E869120,2018-02-17]). Thanks to [user:chokudai,2018-02-17] and [user:rng_58,2018-02-17] to helping us to host the round on AtCoder!<br /> <br /> You will be given <b>100 minutes</b>, and there are <b>4 problems</b> with the following scores: 100 &mdash; 200 &mdash; 300 &mdash; 400.<br /> <br /> This contest is <b>rated</b> for participants whose rating is lower than 1199, but as usual, participants whose rating is more or equal to 1200 can take part out of competition.<br /> <br /> Good luck and have fun!<br /> <br /> <b>UPD: The contest is over. Let's discuss about the problems.</b>

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How to Interpret Contest Ratings **UPDATE: the [new rating system paper](https://arxiv.org/abs/2101.00400) will appear in the Web Conference 2021!** If you're new to competitive programming, you may be wondering: what are ratings and colors? What do they mean? As a contestant and now coach of the UBC team, I've taken enough interest in the subject to have developed my own rating system, Elo-MMR, which I might describe in a future blog post. For now, I want to talk about ratings more generally: what does it mean to achieve a certain rating or title? How concerned should you be with your rating and title? Might it be harmful to be concerned with them at all? A Brief History of Contest Ratings -------------------------------------- Contest rating systems can trace their heritage back to the [Elo system](https://en.wikipedia.org/wiki/Elo_rating_system). Elo was devised for 2-player games, with rating updates based on whether a player wins, loses or draws. Starting in 1960, it was adopted by the chess community ...

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AtCoder Beginner Contest 313 Announcement We will hold AtCoder Beginner Contest 313. - Contest URL: https://atcoder.jp/contests/abc313 - Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20230805T2100&p1=248 - Duration: 100 minutes - Number of Tasks: 8 - Writer: [user:yuto1115,2023-08-04], [user:Nyaan,2023-08-04], [user:math957963,2023-08-04], kyopro_friends, [user:m_99,2023-08-04] - Tester: [user:cn449,2023-08-04], [user:physics0523,2023-08-04] - Rated range: ~ 1999 The point values will be 100-300-400-550-600-625-625-650. Since this contest is used as a qualification round for a local onsite contest, the problems are a bit different from usual ABCs. The style of the problems is a bit closer to ARCs, and the problems are a bit harder. Please refer to previous contests prepared in a similar manner. - https://atcoder.jp/contests/abc262 - https://atcoder.jp/contests/abc288 - https://atcoder.jp/contests/abc290 We are looking forward to your participation!

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Mail.Ru Cup 2018 — Results of R1+R2 Here are merged results of [contest:1054] and [contest:1055] according to the GP100 scores (see the announcement for the details https://mirror.codeforces.com/blog/entry/62355). | Place | Contestant | = | Round 1 | Round 2| | - | - | - | - | - | | 1 | [user:mnbvmar,2018-11-10] | 1497 | 1000 | 497 | | 2 | [user:aid,2018-11-10] | 1204 | 204 | 1000 | | 3 | [user:LHiC,2018-11-10] | 1203 | 497 | 706 | | 4 | [user:V--o_o--V,2018-11-10] | 1150 | 575 | 575 | | 5 | [user:Um_nik,2018-11-10] | 997 | 706 | 291 | | 6 | [user:SpyCheese,2018-11-10] | 742 | 371 | 371 | | 7 | [user:scott_wu,2018-11-10] | 614 | 307 | 307 | | 8 | [user:BudAlNik,2018-11-10] | 531 | 277 | 254 | | 9 | [user:tourist,2018-11-10] | 443 | &mdash; | 443 | | 9 | [user:lewin,2018-11-10] | 443 | 443 | &mdash; | | 11 | [user:Golovanov399,2018-11-10] | 403 | &mdash; | 403 | | 11 | [user:Endagorion,2018-11-10] | 403 | 403 | &mdash; | | 13 | [user:j_______________________,2018-11-10] | 384 | 198 | 186 | | 14 | [...

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Kyoto University Programming Contest 2016 Hi, I would like to invite you to **Kyoto University Programming Contest (KUPC)**, which will be held on [2 Oct. (4:00 &mdash; 9:00 GMT)](https://www.timeanddate.com/worldclock/fixedtime.html?iso=20161002T13&p1=248&ah=5). Problem writers consist of several students in Kyoto University. The contest will be held on [AtCoder](https://atcoder.jp/). <a href="http://kupc2016.contest.atcoder.jp/">Contest Link</a> The contest duration is 5 hours, and there will be 11 problems. KUPC has been held every year for about 5 years in Japan, but this is the first time to provide English problem statements. I participated in the test round of this contest. The first a few problems are easy, so I'm sure everyone can enjoy the contest. On the other hand, a few problems from the last are probably interesting and though enough for high rated coders. We hope lots of people will compete in our contest. Good luck and have fun.

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TCO15 Round2C Just a friendly reminder about [TCO15 Round2C](http://tco15.topcoder.com/algorithm/schedule/). It'll take place in the Japan and online. [Time and Date](http://www.timeanddate.com/worldclock/fixedtime.html?msg=TCO15+Algorithm+Round+2C&iso=20150718T15&p1=248).

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problem with codeforces hey,my round 248 div 2 problem's solution are in queue for more than an hour..m a virtual participant in it...please check it p.s.-i hope the data doesnt get corrupted again :D

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First Ever Users to Reach Some Rating Milestones Revised: ratings below 1500 and greatest rises Several days ago I published a [table](https://mirror.codeforces.com/blog/entry/104320) with first people to reach certain ratings. It featured only ratings above 1500, and [user:adamant,2022-07-09] advised to do the same, but on achieving ratings below 1500. I found it quite interesting, and, after several days of collecting data about participations of 447911 Codeforces users, I finally made this table. [cut] For several reasons I firstly put another table. This is the table of greatest rating rises in the history of Codeforces. The reasons are: 1. I have collected so much data from Codeforces that it would be blasphemy not to use it in as many ways as possible. 2. These tables might intersect a lot: it's easier to get a terrific rise in ratings if you are low-rated. (Many people abuse this and deliberately get very low-rated to make a great jump.) 3. Someone recently posted a table with greatest rating rises and falls. I wasn't able to find this table to check whether it was...

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