Top228 of comments with too negative feedback At one warm winter day I've said to my mother, that I'm going to drink with my friends, but I fooled her: actually I decided to go to a gym. Unfortunately it was closed. I was so sad about it and didn't know what to do: I couldn't return home, because if my mother only knew that I spend my time doing sports she would never give money for buying Jaguar! That's why I went to the nearest padik, turned on russian rap on my mobile phone and started to read some fresh blogs on Codeforces. It was such attractive occupation that I walked to blog of [user:Amir.bh,2015-01-25] with top100 best comments in English. I was greatly inspired by it and I found that this idea is not fully realized. So, it leads me to take one more cup of yazhka. And after that I made this rate. Top 228 comments with negative feedback: <b>1</b>: -600 [user:kursatbakis0,2015-01-24] http://mirror.codeforces.com/blog/entry/13997#comment-189443 <b>2</b>: -271 [user:Makkar,2015-01-24] http://mirror.codeforces.com/blog/entry/9907...

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Educational Codeforces Round 185 Editorial [problem:2170A] Idea: [user:BledDest,2025-11-29] <spoiler summary="Tutorial"> [tutorial:2170A] </spoiler> <spoiler summary="Solution 1 (Neon)"> ~~~~~ #include <bits/stdc++.h> using namespace std; int dx[] = {-1, 0, 1, 0}; int dy[] = {0, -1, 0, 1}; int main() { int t; cin >> t; while (t--) { int n; cin >> n; auto get = [&](int x, int y) { if (x >= 0 && x < n && y >= 0 && y < n) return x * n + y + 1; return 0; }; int ans = 0; for (int i = 0; i < n; ++i) { for (int j = 0; j < n; ++j) { int cur = get(i, j); for (int d = 0; d < 4; ++d) cur += get(i + dx[d], j + dy[d]); ans = max(ans, cur); } } cout << ans << '\n'; } } ~~~~~ </spoiler> <spoiler summary="Solution 2 (Neon)"> ~~~~~ #include <bits/stdc++.h> using namespace std; int main() { int t; cin...

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Solution of 1796F by hard-coding Problem link: [problem:1796F] Let $p =$ number of digits of $n$, $q =$ number of digits of $b$, we have $n=\frac{a \cdot b \cdot (10^{p}-1)}{a \cdot 10^{q}-b}$, by checking every pair of possible $(a, b, p)$ we have a $O(A \cdot B \cdot log(N))$ solution, but it will get TLE. We can modify this solution slightly: let $c=gcd(a, b)$, $k=\frac{a}{c}$, we have $n=\frac{k \cdot b \cdot (10^{p}-1)}{k \cdot 10^{q}-(b/c)}$, because $gcd(k, k \cdot 10^{q}-(b/c))=gcd(k, b/c)=gcd(a/c, b/c)=gcd(a, b)/c=1$, we have $k \cdot 10^{q}-(b/c)$ is divisor of $b \cdot (10^{p}-1)$, therefore, by pre-calculate factors for numbers in range $[1, 100000]$ and in $\{999999, 9999999, 99999999, 999999999\}$, we can check answer for $b$ in $O(\sigma(b) \cdot 185)$, where $\sigma(b)$ is the number of divisors of $b$, and $185=\sum_{p=1}^{9}\sigma(10^{p}-1)$, and we can solve the problem in $O(B \cdot log(B) \cdot 185)$, but this solution still get TLE due to large constant factor of division and modular operat...

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MathDash Round 8 + PRIZES Hello! Would like to invite you all to <a href="https://mathdash.live/contests" rel="noopener noreferrer" style="color: rgb(102, 185, 102);"><strong><u>MathDash Round 8 &mdash; with Prizes!</u></strong></a> on [Tuesday March 5 at 7:30 PM EST (4:30PM PST)](https://www.timeanddate.com/worldclock/fixedtime.html?msg=Math+Dash+Round+8&iso=20240305T1630&p1=224&ah=2). You will be offered 10 problems to solve. The prize fund for this round will be <strong style="color: rgb(102, 185, 102);">$110</strong> The top five contestants of Silver will get <strong style="color: rgb(102, 185, 102);">$25 &mdash; $20 &mdash; $20 &mdash; $20 &mdash; $15</strong> respectively. The top contestant in Bronze gets <strong style="color: rgb(102, 185, 102);">$10</strong> Tiebreaks will be done first by number of submissions and then by time of last correct submission. We were super happy to see all the participation in Contest 7, our largest contest ever! Congratulations to the winners :) <strong...

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Invitation to TOKI Open 2017 Hello! After we successfully organized [TOKI Open 2014](http://mirror.codeforces.com/blog/entry/12286), we are going to do the similar thing this year. We will open our current IOI Selection Contest to international participants. We call it **TOKI Open 2017**. TOKI stands for Tim Olimpiade Komputer Indonesia, or Indonesian Computing Olympiad Team in English. Objectives of us opening this contest include, but not limited to: - Measure the performance of our IOI trainee compared to other countries' IOI trainee. - Foster friendship between Indonesia and other IOI participating countries. - Test Indonesia's scientific committee capability in setting IOI-level problems. - Test Indonesia's technical committee capability in hosting IOI-level contests. The contest will have very similar format with IOI, as this contest will be used to select our Top 4 and train our Top 4 for IOI. We expect that the difficulty of the contest is almost the same as IOI. Therefore, this contest is su...

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MathDash Rounds 10, 11, and 12 with $360 in Prizes! Hello! Would like to invite you all to four contests this week :) <a href="https://mathdash.live/contests" rel="noopener noreferrer" style="color: rgb(102, 185, 102);"><strong><u>MathDash Round 10 &mdash; with Prizes!</u></strong></a> on [Monday March 18 at 7:30 PM EST (4:30PM PST)](https://www.timeanddate.com/worldclock/fixedtime.html?msg=Math+Dash+Round+10&iso=20240318T1630&p1=224&ah=2). <a href="https://mathdash.live/contests" rel="noopener noreferrer" style="color: rgb(102, 185, 102);"><strong><u>MathDash Round 11 &mdash; with Prizes!</u></strong></a> on [Wednesday March 20 at 7:30 PM EST (4:30PM PST)](https://www.timeanddate.com/worldclock/fixedtime.html?msg=Math+Dash+Round+11&iso=20240320T1630&p1=224&ah=2). <a href="https://mathdash.live/contests" rel="noopener noreferrer" style="color: rgb(102, 185, 102);"><strong><u>MathDash Mock MATHCOUNTS Sprint</u></strong></a> on [Thursday March 21 at 7:30 PM EST (4:30PM PST)](https://www.timeanddate.com/worldclock/fixedtime.html?m...

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Codeforces Round #185 Hello,everyone! Codeforces Round #185 will take place on [Sunday, May 26th at 19:30MSK (23:30CST)](http://www.timeanddate.com/worldclock/fixedtime.html?day=26&month=5&year=2013&hour=19&min=30&sec=0&p1=166). This round is initiated by [user:Zanoes,2013-05-25], and here are the problem setters: - Div.1E & Div.2B —— [user:Zanoes,2013-05-25] (**Zhang Gaoxiang**) - Div.1D & Div.1A —— [user:liouzhou_101,2013-05-25] (**Wang Qisheng**) - Div.1C & Div.1B & Div.2A —— [user:lydrainbowcat,2013-05-25] (**Li Yudong**) Testers are [user:roosephu,2013-05-25](Luo Yuping), [user:FredaShi,2013-05-25](Shi Haoyue), [user:sjynoi,2013-05-25](Sun Jiayu), [user:sevenkplus,2013-05-25](Gu Yuzhou), [user:xiaodao,2013-05-25](Tang Feihu) and [user:Riatre,2013-05-25]. Especially thanks [user:Gerald,2013-05-25] for helping us to prepare the round, [user:MikeMirzayanov,2013-05-25] for the great platform and [user:Delinur,2013-05-25] for translation. Score will be standard...

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Invitation to CodeChef Starters 185 (Rated till 5-Stars) - 7th May We invite you to participate in CodeChef’s [Starters 185](https://www.codechef.com/START185), this Wednesday, 7th May, rated for 5 star (i.e. for users with rating < 2200). Time: [8:00 PM — 10:00 PM IST](https://www.timeanddate.com/worldclock/fixedtime.html?msg=CodeChef+Starters+185&iso=20250507T20&p1=44&ah=2) Joining us on the problem setting panel are: - Contest Admin, Statement Verifier, and Text Editorialist: Nishank [user:IceKnight1093,2025-05-07] Suresh. - Tester: Sushil [user:SmolBrain,2025-05-07] Raaja. - Setter: Nishank [user:IceKnight1093,2025-05-07] Suresh. Written editorials will be available for all on discuss.codechef.com. Pro users can find the editorials directly on the problem pages after the contest. The video editorials of the problems will be available only to Pro users. Also, if you have some original and engaging problem ideas, and you’re interested in them being used in CodeChef's contests, you can share them [here](https://www.codechef.com/...

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Codeforces Top 100 Comments Hi guys, Here you can find Top 100 Comments in the history of Codeforces Til 1 Jan 2015. It reminds us of some memories we had together in Codeforces :) ### Top 100 [user:yeputons,2015-01-01] 448 http://mirror.codeforces.com/blog/entry/8063#comment-138056 [user:zeulb,2015-01-01] 438 http://mirror.codeforces.com/blog/entry/10193#comment-156433 [user:Petr,2015-01-01] 354 http://mirror.codeforces.com/blog/entry/12605#comment-174158 [user:zakharvoit,2015-01-01] 326 http://mirror.codeforces.com/blog/entry/12605#comment-174167 [user:ashmelev,2015-01-01] 318 http://mirror.codeforces.com/blog/entry/4302#comment-87389 [user:tourist,2015-01-01] 307 http://mirror.codeforces.com/blog/entry/7499#comment-133421 [user:MikeMirzayanov,2015-01-01] 305 http://mirror.codeforces.com/blog/entry/1767#comment-33686 [user:Gogis,2015-01-01] 297 http://mirror.codeforces.com/blog/entry/15511#comment-204474 [user:sorry_dreamoon,2015-01-01] 287 http://mirror.codeforces.com/blog/entry/15336#comment-202752 [user:MikeMirzayanov,2015-01-01] 286 h...

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Invitation to TOKI Open Contest March 2018 Hello Codeforces Community, TOKI Open Contest is back again! :D We would like to invite you to participate in this TOKI Open Contest March 2018. TOKI Open Contest is Indonesian (bi-)monthly online programming contest. You may see the January 2018 contest [here](http://mirror.codeforces.com/blog/entry/57280)! :) Every problem is written in both Bahasa Indonesia and English. The contest will be divided into **two divisions**: Division 1 and Division 2. It is pretty similar to the divisions in [Atcoder](http://atcoder.jp/) (Beginner and Regular). You are free to register in any division (it's extremely OK if you are a Div2 Codeforces user and register to our Division 1 contest)! The expected difficulties of the problems are much the same with Atcoder's contest problems. TOKI Open Contest March 2018 will be held on [Saturday, 24 March 2018, 19.00 — 21.00 Western Indonesian Time (UTC+7)](https://www.timeanddate.com/worldclock/fixedtime.html?msg=TOKI+Open+Contest+March+2018&iso=20180324T19...

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GoForGold IOI Bootcamp — India <center> <img height="100px" src="/predownloaded/67/2f/672f239a4b390e85db2408790f5907770547fdb2.jpeg"> <img height="90px" src="/predownloaded/6b/b4/6bb4c1baf053e08ac2257bee4fe8c479b133272b.png"> </center> Hi everyone! We are thrilled to announce that the [GoForGold](https://goforgold.in/) IOI Bootcamp is coming this Summer, on **May 25-June 6, 2025**! After carefully considering various academic schedules, competition dates, and feedback from our community, we've selected these dates to accommodate as many talented young programmers as possible. This intensive training program will be hosted at the [Newton School of Technology](https://www.newtonschool.co/newton-school-of-technology-nst/home) Campus in Sonipat, Delhi, and is brought to you by the GoForGold. The bootcamp is specifically designed to prepare talented students for the International Olympiad in Informatics by providing intensive training, practice, and mentorship. Our goal is to expand India's competitive pr...

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Welcome to LibreOJ "Hello WuXu" Round!  ### [Contest Link](https://loj.ac/contest/22) > The night falls usually, while the street lights are shining; > > The new year came quietly, with the bells of temples ringing. > > The splendours and hardships of the bygones has faded away, rendering centuries of reality as transient as fleeting clouds; > > And the uncertainties and probabilities of the future is yet to come, making the shared offing between you and me. The Lunar New Year is here! Out with the old, in with the new, [LibreOJ](https://loj.ac/) is holding a grand contest for the Year of Wuxu. The round will be similar to a normal Codeforces Div.1 round in difficulty. We have picked some interesting ideas for this round, and partial-score subtasks will be available. We believe that all participants can get quite a bit from them. The round will be held on IOI rules with no submission limit, the scores of different problems will be different. ...

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Educational Codeforces Round 54 [Rated for Div. 2] On [contest_time:1076] [contest:1076] 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. 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 **7 problems** and **2 hours** to solve them. The problems were invented and prepared by Roman [user:Ajosteen,2018-10-24] Glazov, Adilbek [user:adedalic,2018-10-24] Dalabaev, Vladimir [user:Vovuh,2018-10-24] Petrov, Ivan [user:BledDest,2018-...

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Educational Codeforces Round 81 [Rated for Div. 2] Hello Codeforces! On [contest_time:1295] [contest:1295] 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 problems** and **2 hours** to solve them. The problems were invented and prepared by Roman [user:Roms,2020-01-13] Glazov, Adilbek [user:adedalic,2020-01-13] Dalabaev, Vladimir [user:Vovuh,2020-01-13] Petrov, Ivan [user:Bl...

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Codeforces Educational Round 185 (Div 2) — Solution Discussion **Note: The text editorial is/will be provided by the authors of the round. This video tutorial acts as an additional resource for those who prefer video over text, not as a substitute for the text editorial.** ### [2170A &mdash; Maximum Neighborhood](https://mirror.codeforces.com/contest/2170/problem/A) <spoiler summary="Video"> <iframe width="800" height="450" src="https://www.youtube.com/embed/wE24vM6A_Sc?si=GpsTvGe2e6ccb3Hz&amp;start=224" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe> </spoiler> ### [2170B &mdash; Addition on a Segment](https://mirror.codeforces.com/contest/2170/problem/B) <spoiler summary="Video"> <iframe width="800" height="450" src="https://www.youtube.com/embed/wE24vM6A_Sc?si=GpsTvGe2e6ccb3Hz&amp;start=794" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay;...

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Unofficial Editorial for AtCoder Beginner Contest #185 [A &mdash; ABC Preparation](https://atcoder.jp/contests/abc185/tasks/abc185_a) ============================================================== <spoiler summary="Solution"> Since we need exactly one of each of $A_1$, $A_2$, $A_3$ and $A_4$, we are limited by the minimum number we have of one of these. Therefore, we need to print the minimum element of these four. [My solution](https://atcoder.jp/contests/abc185/submissions/18767215) </spoiler> [B &mdash; Smartphone Addiction](https://atcoder.jp/contests/abc185/tasks/abc185_b) ============================================================== <spoiler summary="Solution"> If Takahashi's phone is to run out of battery during his walks between two of the locations, it will be at an even lesser battery at the end of that walk. So, we simply need to check that upon entering one of the $M$ cafes, or returning to his house, that his phone's battery is greater than 0, and increase his battery by $y_i-x_i$ for each of the cafes, whi...

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Live online mirror of The 2019 ICPC Asia Jakarta Regional Contest Hi, We would like to invite you to participate in the live (with 30-minute delay) [online mirror contest of The 2019 ICPC Asia Jakarta Regional Contest](https://mirror.codeforces.com/contest/1252) ([our regional website](https://competition.binus.ac.id/icpc2019/), [our regional in ICPC website](https://icpc.baylor.edu/regionals/finder/Jakarta-2019), [official contest portal](https://competition.binus.ac.id/contest)) this weekend. The online mirror contest will start on [contest_time:1252]. The contest consists of several problems and you can solve them in 5 hours. See you on top of the leaderboard. **UPD1:** Thanks for participating. The problems should be available for upsolving. The soft-copy of the problem analysis (the same as the one distributed to all contestants during the awarding ceremony) is available [here](https://github.com/jonathanirvings/icpc-jakarta-2019/blob/master/problem_analysis.pdf). **UPD2:** The full problem repository is available [here](https://github.c...

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Codeforces Round #185 Editorial #### [problem:311A] [http://mirror.codeforces.com/blog/entry/7787](http://mirror.codeforces.com/blog/entry/7787) #### [problem:311B] P.S. I feel very sorry that I thought it was a traditional DP problem with only 800B code and didn't realize some participants were not familiar with such kind of problems, so I said it was easy. Let a[i] be the distance from hill 1 to hill i, s[i]=a[1]+a[2]+…+a[i]. Firstly, we sort the cats by (Ti-a[i]). Then we can divide the cats into P consecutive parts, and plan a feeder for each part. **Dynamic Programming** can solve this problem. Let f[i,j] indicates the minimum sum of waiting time with i feeders and j cats. f[i,j] = f[i-1,k]+a[j]*(j-k)-s[j]+s[k] = a[j]*j-s[j] + f[i-1,k]+s[k]-a[j]*k That’s O(PM^2). It’ll get TLE. Let p>q, if p is "better" than q, then: f[i-1,p]+s[p]-a[j]*p>f[i-1,q]+s[q]-a[j]*q (f[i-1,p]+s[p])-(f[i-1,q]+s[q])>a[j]*(p-q) g[p]-g[q]>a[j]*(p-q) So we can use **Convex hull trick** with a queue. Then we get O(MP),...

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AtCoder Beginner Contest 185 Announcement We will hold AtCoder Beginner Contest 185. - Contest URL: https://atcoder.jp/contests/abc185 - Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20201213T2100&p1=248 - Duration: 100 minutes - Number of Tasks: 6 - Writer: [user:beet,2020-12-13], [user:rapca,2020-12-13], [user:kobae964,2020-12-13], [user:kort0n,2020-12-13], kyopro_friends, [user:QCFium,2020-12-13], [user:satashun,2020-12-13] - Rated range: ~ 1999 The point values will be 100-200-300-400-500-600. We are looking forward to your participation!

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Баллы заключительного этапа ВсОШ 2025 versus пиковый рейтинг на CodeForces Когда-то давно я участвовал в заключительном этапе ВсОШ по информатике, а сейчас решил сравнить уровень современных участников и свой, используя рейтинг на Codeforces. Для этого можно сначала узнать как зависят [баллы заключительного этапа ВсОШ 2025](https://nerc.itmo.ru/school/archive/2024-2025/ru-olymp-roi-2025-standings.html) от максимального рейтинга на Codeforces на дату проведения олимпиады.  Показаны данные для: [user:abs0lute,2026-02-06] [user:ace5,2026-02-06] [user:AI-qv4rk,2026-02-06] [user:al3x.selivanov,2026-02-06] [user:AlexW08,2026-02-06] [user:Amirkhan_Zakirov,2026-02-06] [user:Andrei_Kuz,2026-02-06] [user:arbuzick,2026-02-06] [user:ArSarapkin,2026-02-06] [user:ArtemUstimenko,2026-02-06] [user:artimovich.ko,2026-02-06] [user:aslashkin2010,2026-02-06] [user:bashkort,2026-02-06] [user:Chugunov_Alexander,2026-02-06] [user:const,2026-02-06] [user:cot-in,2026-02-06] [user:cSERAFIMc,20...

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About 2031C (Penchick and BBQ Buns, problem C of CF Round 987), and extra challenges Author of the problem [problem:2031C] here, hope you enjoyed the contest yesterday (Almost exactly 24 hours ago...)! Looking at the votes on [the editorial](https://mirror.codeforces.com/blog/entry/136260), it's obvious that it's a very polarizing problem: an hour or so after the contest, the problem had roughly equal numbers of "likes" and "dislikes", and now (as of writing) there are around 320 likes to 200 dislikes. Of course, this is completely predictable: the opinions on this problem were quite polarized for a few reasons: 1. Troll and WA trap: it's **very** easy to fall into the trap of thinking that there is no solution for all odd $n$; thus, **over 12,900** (!) WA on pretest 2 solutions were received, as compared to only 4,700ish Accepted solutions. This ratio seems a bit extreme for a problem C; in the previous Div.2's problem C ([problem:2028C]), there were 3,500ish Rejected solutions to 2,500ish Accepted ones. 2. The construction: hard-coding the case $n=27$ seems weird an...

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Hack me! (Codeforces Round #277.5 (Div. 2)) Welcome after the long break in Hack me! ([contest:489]). Previous posts can be found [here](http://mirror.codeforces.com/search?query=hackme). [cut] <h3>Stats</h3> Problem | <small>Successful hacks</small> | <small>Unsuccessful hacks</small> | Other* | Sum | <small>Solutions which can be hacked</small> | <small>Accepted solutions</small> | <small> All solutions on final tests</small>| :---:|:---:|:---:|:---:|:---:|:---:| <small> [problem:489A] </small> | 11 (28.21%) | 24 (61.54%)| 4 (10.26%) | 39 | 400 (17.22%) | 1923 (82.78%) | 2323 | <small> [problem:489B] </small> | 185 (61.26%) | 102 (33.77%)| 15 (4.97%) | 302 | 427 (18.09%) | 1934 (81.91%) | 2361 | <small> [problem:489C] </small> | 8 (11.59%) | 59 (85.51%)| 2 (2.90%) | 69 | 158 (8.90%) | 1618 (91.10%) | 1776 | <small> [problem:489D] </small> | 2 (14.29%) | 6 (42.86%)| 6 (42.86%) | 14 | 38 (4.99%) | 724 (95.01%) | 762 | <small> [problem:489E] </small> | 0 | 0 | 0 | 0 | 23 (41.07%) | 33 (58.93%)| 56 | <small> [problem:4...

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Hack me! (Bayan 2015 Contest Warm Up) Welcome in [contest:475] hacks description. This round was pretty good for hackers, but again there were nearly two times more unused opportunities for hack than the used ones. Let's look at them. If you want to share your hack (or mistake) -- we're waiting for your comments. Previous posts can be found [here](http://mirror.codeforces.com/search?query=hackme). [cut] <h3>Stats</h3> Problem | <small>Successful hacks</small> | <small>Unsuccessful hacks</small> | Other | Sum | <small>Solutions which can be hacked</small> | <small>Accepted solutions</small> | <small> All solutions on final tests</small>| :---:|:---:|:---:|:---:|:---:|:---:| <small> [problem:475A] </small> | 243 (53.06%) | 205 (44.76%)| 10 (2.18%) | 458 | 349 (15.73%) | 1869 (84.27%) | 2218 | <small> [problem:475B] </small> | 94 (50.81%) | 72 (38.92%)| 19 (10.27%) | 185 | 192 (10.35%) | 1663 (89.65%) | 1855 | <small> [problem:475C] </small> | 6 (14.63%) | 26 (63.41%)| 9 (21.95%) | 41 | 113 (25.80%) | 325 (74.20%)...

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MathDash Round 9! FOUR Division and $120 in Prizes! Hello! Would like to invite you all to <a href="https://mathdash.live/contests" rel="noopener noreferrer" style="color: rgb(102, 185, 102);"><strong><u>MathDash Round 9 &mdash; with Prizes!</u></strong></a> on [Monday March 11 at 7:30 PM EST (4:30PM PST)](https://www.timeanddate.com/worldclock/fixedtime.html?msg=Math+Dash+Round+8&iso=20240311T1630&p1=224&ah=2). You will be offered 10 problems to solve. The prize fund for this round will be <strong style="color: rgb(102, 185, 102);">$120</strong> The top three contestants of Gold/Plat will get <strong style="color: rgb(102, 185, 102);">$25 &mdash; $20 &mdash; $15</strong> respectively. The top two contestants of Silver will get <strong style="color: rgb(102, 185, 102);">$20 &mdash; $15</strong> respectively. The top contestants in Bronze and Iron will get <strong style="color: rgb(102, 185, 102);">$15 &mdash; $10 &mdash</strong> respectively. We really enjoy putting on these rounds for you all. Would love to hear feedbac...

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Haskell solutions For those who are interested, here is a list of all problems for which Haskell solutions have been submitted. (Use the 'Status filter' to show only the Haskell submissions.) [1A](http://mirror.codeforces.com/problemset/status/1/problem/A) [1B](http://mirror.codeforces.com/problemset/status/1/problem/B) [1C](http://mirror.codeforces.com/problemset/status/1/problem/C) [2A](http://mirror.codeforces.com/problemset/status/2/problem/A) [2B](http://mirror.codeforces.com/problemset/status/2/problem/B) [2C](http://mirror.codeforces.com/problemset/status/2/problem/C) [3A](http://mirror.codeforces.com/problemset/status/3/problem/A) [3B](http://mirror.codeforces.com/problemset/status/3/problem/B) [3C](http://mirror.codeforces.com/problemset/status/3/problem/C) [3D](http://mirror.codeforces.com/problemset/status/3/problem/D) [4A](http://mirror.codeforces.com/problemset/status/4/problem/A) [4B](http://mirror.codeforces.com/problemset/status/4/problem/B) [4C](http://mirror.codeforces.com/problemset/status/4/problem/C) [4D](http://mirror.codeforces.com/problemset/status/4/problem/D)...

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MathForces - Arithmetic Dash: 2 minute test Hey! Wanted to share with you all the Arithmetic Dash! **Rated** <b>Arithmetic Dash 1:</b> <a href="https://mathdash.live/contest/arithmetic-dash-1">Start Test</a><br> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- <b>Arithmetic Dash 2:</b> <a href="https://mathdash.live/contest/arithmetic-dash-2">Start Test</a><br> -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------  <b>Format:</b> You will be given 2 minutes to answer as many arithmetic questions as...

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One Day , One Problem Story Hi , this is my today tough story and pictorial editorial for problem 389D/388B. ( first of all sorry for my english ) After lunch I decided to solve a hard problem ( compared to my skills ) [Fox and Minimal path](http://mirror.codeforces.com/problemset/problem/388/B). Problem wants a graph that total number of shortest paths between nodes 1,2 will be k (1<=k<=1e9). but I didn't know a simple condition will kill me today ... you can use at most 1000 nodes. first time I decided to decompose k to prime factors and create paths like this :  I couldn't find any solution for big primes! but because I thought my solution is true so they will not be in test cases !!! After coding , submitting and getting [WA on test 11](http://mirror.codeforces.com/contest/388/submission/12958756) , and having no idea for another solution , I decided to read the editorial . After reading the editorial I found that I am so stupid , why I forg...

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MathForces Daily Round 8 — 24 Hours, Div 1 — Div 5! Hello! We would love to invite you to <a href="https://mathdash.live/contests" rel="noopener noreferrer" style="color: rgb(102, 185, 102);"><strong><u>MathDash Daily 8</u></strong></a> today any time within the next $24$ hours! You will be offered 10 problems to solve in 40 minutes. The level is Math from a Div 5 level all the way to Div 1 level. The round will be <b style="color: rgb(102, 185, 102);">rated</b> for ratings 1600 and below. There will be five different divisions: Iron, Bronze, Silver, Gold, and Platinum. <b><u><a href="https://mathdash.live/contests" rel="noopener noreferrer" style="color: rgb(0, 0, 255);">Enter here</a></u></b>. We ask that you **do not discuss the problems until 24 hours from now** (i.e. after the Contest ends) &mdash; but general discussion/suggestions are welcome and encouraged below! Feel free to join our community <a href="https://discord.gg/ccDPnqS42z" rel="noopener noreferrer" style=""><u>in Discord</u></a> or email us ( coach@mathdash.liv...

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Lightning Rounds 4, 5, 6, 7 today at 7,7:30,8,8:30PM ET Hello Codeforces! We are hosting four live and exciting **rated** 15-minute 15-problem rounds, at [7 PM](https://www.timeanddate.com/worldclock/fixedtime.html?msg=Math+Dash+Round+10&iso=20240426T1600&p1=224&am=15) for the Under 1400 division, and then [7:30 PM](https://www.timeanddate.com/worldclock/fixedtime.html?msg=Math+Dash+Round+10&iso=20240426T1630&p1=224&am=15), [8 PM](https://www.timeanddate.com/worldclock/fixedtime.html?msg=Math+Dash+Round+10&iso=20240426T1700&p1=224&am=15), and [8:30 PM](https://www.timeanddate.com/worldclock/fixedtime.html?msg=Math+Dash+Round+10&iso=20240426T1730&p1=224&am=15) for everyone! (all ET) &mdash; This is a cool opportunity to compete with some really good mathletes! You can <a href="https://mathdash.live/contest/lightning5" rel="noopener noreferrer" style="color: rgb(102, 185, 102);"><strong>Register Here</strong></a> for Lightning 4, 5, 6, and 7 (note: this will take you to Lightning 5, you can click on 'Contests' to register for the others...

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MathDash Daily Round 9 - Div 1 thru Div 5! Hello! We would love to invite you to <a href="https://mathdash.live/contests" rel="noopener noreferrer" style="color: rgb(102, 185, 102);"><strong><u>MathDash Daily 9</u></strong></a> today any time within the next $24$ hours! You will be offered 9 or 10 problems to solve in 40 minutes. The level is Math from a Div 5 level all the way to Div 1 level. The round will be <b style="color: rgb(102, 185, 102);">rated</b> for ratings 1600 and below. There will be five different divisions: Iron, Bronze, Silver, Gold, and Platinum. <b><u><a href="https://mathdash.live/contests" rel="noopener noreferrer" style="color: rgb(0, 0, 255);">Enter here</a></u></b>. We ask that you **do not discuss the problems until 24 hours from now** (i.e. after the Contest ends) &mdash; but general discussion/suggestions are welcome and encouraged below! Feel free to join our community <a href="https://discord.gg/ccDPnqS42z" rel="noopener noreferrer" style=""><u>in Discord</u></a> or email us ( coach@mathdas...

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Codeforces Round #185 Editorial (Div.1 A&D) #### [311A &mdash; The Closest Pair](http://mirror.codeforces.com/problemset/problem/311/A) P.S. I feel really guilty that I've made an awful mistake on the checker. We read the pseudo code carefully. If we ignore "break", $tot$ will be up to $\frac{n(n-1)}{2}$. Consider whether we can make such inequality $d \leq p[j].x-p[i].x$ is always false. The obvious way is to make all points' x coordinates the same. And we can just choose $n$ distinct numbers to be all points' y coordinate. Thus the problem is solved. #### [311D &mdash; Interval Cubing](http://mirror.codeforces.com/problemset/problem/311/D) Consider a number $x$. If we apply an assignment $x=x^3$, $x$ becomes $x^3$. If we apply such assignment once more, we will get $(x^3)^3 = x^{3^2}$. If we apply such assignment $k$ times, we will get $x^{3^k}$. Thus, we can get such a sequence $a_0=x, a_1=x^3, a_2=x^{3^2}, \dots, a_k=x^{3^k}, \dots$. Consider a prime $p$. From Fermat's Little Theorem, we can get $x^{p-1}=1(mod$ $p)...

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AtCoder Regular Contest 185 Announcement We will hold AtCoder Regular Contest 185. - Contest URL: https://atcoder.jp/contests/arc185 - Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20241013T2100&p1=248 - Duration: 120 minutes - Number of Tasks: 5 - Writer: [user:Nyaan,2024-10-12] - Tester: [user:maspy,2024-10-12] - Rated range: 1200 ~ 2799 The point values will be 600-600-600-800-800. We are looking forward to your participation!

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MathForces — TODAY for 24 hours!! Hello! One of MathDash's most common requests has been to accomodate people in other time zones. This is now possible &mdash; we would love to invite you to <a href="https://mathdash.live/contest/daily6" rel="noopener noreferrer" style="color: rgb(102, 185, 102);"><strong><u>MathDash Daily 6</u></strong></a> today any time within the next $24$ hours! You will be offered 15 problems to solve. The level is Math from a Div 4 level all the way to Div 1 level. The round will be <b style="color: rgb(102, 185, 102);">rated</b>. <b><u><a href="https://mathdash.live/contest/daily6" rel="noopener noreferrer" style="color: rgb(0, 0, 255);">Enter here</a></u></b>. We ask that you **do not discuss the problems until 24 hours from now** (i.e. after the Contest ends) &mdash; but general discussion/suggestions are welcome and encouraged below! Feel free to join our community <a href="https://discord.gg/ccDPnqS42z" rel="noopener noreferrer" style=""><u>in Discord</u></a> or email us ( coach@math...

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Первая личная интернет-олимпиада + Первый отбор на ИОИП, Сезон 2019-20 <img align="right" src="/predownloaded/f9/f4/f9f4375d321146292da14e984bc7bba573fe7748.png"/> Всем привет! 26 января в 12:00 состоится первая личная интернет-олимпиада для школьников, которая также будет являться первым отборочным раундом на ИОИП-2020. Приглашаем вас принять в ней участие! Продолжительность олимпиады — 5 часов. Не забудьте [зарегистрироваться](http://neerc.ifmo.ru/school/io/registerIndividual.jsp) на цикл личных интернет-олимпиад в этом сезоне перед началом олимпиады. Обратите внимание, что для участия в личных олимпиадах, нужно зарегистрировать **участника** (по ссылке "Новый участник"). Дополнительную информацию, а также расписание всех предстоящих интернет-олимпиад можно посмотреть на [страничке интернет-олимпиад](http://neerc.ifmo.ru/school/io). Условия появятся на сайте в момент начала олимпиады, а также на вкладке "Файлы" в тестирующей системе. Тестирующая система находится по адресу [pcms.itmo.ru](http://pcms.itmo.ru). Олимпиаду для вас подготовили...

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Introduction to One Dimensional Fenwick-Tree And Relative Mapping For Calculating Prefix Sums The Following Introduction to The Fenwick Tree is Intended to be Easy to Understand and Targeted At Newbies , any Suggestion to make it Easier Will be Appreciated I was Introduced to Competitive Programming a Few weeks Ago Precisely Three and One of the First Data Structures i Encountered Was The Fenwick Tree, Its one of The Most Easy to Implement Form of Binary Indexed Trees out There and greatly Helps in Solving Problems With Deal With Statistical Cumulative Frequency of a Class , NOTE : Here Class Represents Statistical Interval Range And Not OOP Concept <strong>Firstly Some of The Basic Concepts Relating To Cumulative Frequency :</strong> Lets Say I Have to Add Marbles to a Particular Box (From a Range of Boxes ) and Then Report The Query of The Following Type From The Data : <ul> <li>The Total Number of Marbles</li> <li>The Total Number of Marbles From Box U to V;</li> <li>Marbles in Box U</li> </ul> Lets Say I Have the Following Data For Four Marble Boxes <table> <...

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Educational Codeforces Round 185 [Rated for Div. 2] <img alt="Neapolis University Pafos" src="/predownloaded/9a/33/9a332fadbb47050ba9405057df022a6e37eaf5c0.png" style="float:right;height: 200px; margin: 10px; max-width:40%;"/> Hello Codeforces! The series of Educational Rounds continues thanks to the support of the [Neapolis University Pafos](https://www.nup.ac.cy/). On [contest_time:2170] [contest:2170] will start. This round will be **rated for the participants with rating lower than 2100**. It will be held on extended ICPC rules. The penalty for each incorrect submission until the submission with a full solution is 10 minutes. After the end of the contest, you will have 12 hours to hack any solution you want. You will have access to copy any solution and test it locally. You will be given **6 or 7 problems** and **2 hours** to solve them. The problems were invented and prepared by Adilbek [user:adedalic,2025-11-27] Dalabaev, Ivan [user:BledDest,2025-11-27] Androsov, Maksim [user:Neon,2025-11-27] Mescheryakov, Ro...

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Weird Precision Behavior in "Inline Function" on GNU C++17 7.3.0 I was solving the problem [185B/186D](https://mirror.codeforces.com/problemset/problem/185/B). Then I encountered a weird issue. I got WA on test $8$ in this submission: [123642519](https://mirror.codeforces.com/problemset/submission/185/123642519). But, when I made the solve function inline, it passed test $8$ (though it got WA on test $31$): [123642504](https://mirror.codeforces.com/problemset/submission/185/123642504). In test $8$, the submission without inlined solve function prints `2.712800440549510 6.287199559450490 0.000000000000000` as output. On the other hand, the submission with inlined solve function prints `2.700961045920403 6.299038954079596 0.000000000000000` as output. So, the outputs have significant precision differences. My question is, how the inlined function has an impact on precision? It will be very helpful if anybody gives an insight.

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Codeforces Round #185 Editorial (Div.2 B&Div.1 E) [problem:312B] let p=a/b,q=(1-c/d)*(1-a/b). The answer of this problem can be showed as:p*q^0+p*q^1+p*q^2+………… That is the sum of a geometric progression which is infinite but 0<q<1.We can get the limit by the formula:p/(1-q) [problem:311E] Obviously, It is about min-cut, which can be solved by max-flow. So, this problem can regarded as the minimum of losing money if we assume SmallR can get all the money and get a total money(sum of wi)at first. Define that, in the min-cut result, the dogs which are connected directly or indirectly to S are 0-gender.otherwise, those to T are 1-gender.We can easily find that the point of a initial-0-gender dog should get a vi weight edge to S.On the other way, initial-1-gender to T. Then, consider the rich men.As to each of rich men, he can appoint only one gender and some dogs.if any one dog he appoint is not the one appointed gender in the result, he can't give SmallR money.How to deal with the rich men in the graph is a difficulty...

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MathForces Daily Round 7 Today 24-hours! Hello! We would love to invite you to <a href="https://mathdash.live/contest/daily7" rel="noopener noreferrer" style="color: rgb(102, 185, 102);"><strong><u>MathDash Daily 7</u></strong></a> today any time within the next $24$ hours! You will be offered 18 problems to solve. The level is Math from a Div 4 level all the way to Div 1 level. The round will be <b style="color: rgb(102, 185, 102);">rated</b> for ratings 1400 and below. <b><u><a href="https://mathdash.live/contest/daily7" rel="noopener noreferrer" style="color: rgb(0, 0, 255);">Enter here</a></u></b>. We ask that you **do not discuss the problems until 24 hours from now** (i.e. after the Contest ends) &mdash; but general discussion/suggestions are welcome and encouraged below! Feel free to join our community <a href="https://discord.gg/ccDPnqS42z" rel="noopener noreferrer" style=""><u>in Discord</u></a> or email us ( coach@mathdash.live )!</p>

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MathDash Mock MATHCOUNTS Sprint Today! Hello! Would like to invite you all to <a href="https://mathdash.live/contest/mathcounts1" rel="noopener noreferrer" style="color: rgb(102, 185, 102);"><strong><u>MathDash Mock MATHCOUNTS Sprint</u></strong></a> on [Thursday March 14 at 8:30 PM EST (5:30PM PST)](https://www.timeanddate.com/worldclock/fixedtime.html?msg=Math+Dash+Round+8&iso=20240314T1730&p1=224&ah=2). You will be offered 30 problems to solve. The round will be <b style="color: rgb(102, 185, 102);">rated</b>. <b><u><a href="https://mathdash.live/contest/mathcounts1" rel="noopener noreferrer" style="color: rgb(0, 0, 255);">Register here</a></u></b>. We really enjoy putting on these rounds for you all. Would love to hear feedback and suggestions <a href="https://discord.gg/ccDPnqS42z" rel="noopener noreferrer" style=""><u>in Discord</u></a> or via email ( coach@mathdash.live )!</p>

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Announcing MathDash Daily Round 1 Hello! Would like to invite you all to our new **daily** series of contests &mdash; <a href="https://mathdash.live/contests" rel="noopener noreferrer" style="color: rgb(102, 185, 102);"><strong><u>MathDash Daily Round 1</u></strong></a> on [Wednesday March 6 at 9PM EST (6PM PST)](https://www.timeanddate.com/worldclock/fixedtime.html?msg=Math+Dash+Round+8&iso=20240306T1800&p1=224&ah=2). You will be offered 10 problems to solve. We are also giving out a prize for each of these daily contests &mdash; <strong style="color: rgb(102, 185, 102);">$10</strong> to the top ranked participant in grade 8 or under (or the equivalent in the country of the participant) We're bringing you CodeForces for Math &mdash; would love to have you join us on this journey. If you're excited for this round, please comment your favorite math topic :)

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Who is the most popular? Looks like noone has already done this. Here is top100 of the most popular users on the codeforces. (the list contains only users from top200 by rating or top200 by contribution) | # | User | Followers | | --- | --- | --- | | 1 | [user:tourist,2015-10-18] | 4721 | | 2 | [user:Petr,2015-10-18] | 2351 | | 3 | [user:rng_58,2015-10-18] | 1472 | | 4 | [user:WJMZBMR,2015-10-18] | 1431 | | 5 | [user:Egor,2015-10-18] | 974 | | 6 | [user:ahmed_aly,2015-10-18] | 886 | | 7 | [user:xiaodao,2015-10-18] | 825 | | 8 | [user:I_love_Tanya_Romanova,2015-10-18] | 797 | | 9 | [user:ACRush,2015-10-18] | 790 | | 10 | [user:dreamoon,2015-10-18] | 786 | | 11 | [user:yeputons,2015-10-18] | 709 | | 12 | [user:ftiasch,2015-10-18] | 659 | | 13 | [user:niyaznigmatul,2015-10-18] | 655 | | 14 | [user:adurysk,2015-10-18] | 617 | | 15 | [user:scott_wu,2015-10-18] | 615 | | 16 | [user:sevenkplus,2015-10-18] | 569 | | 17 | [user:cgy4ever,2015-10-18] | 527 | | 18 | [user:PrinceOfPersia,2015-10-18...

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Республиканская олимпиада 2026 года. Казахcтан. Результаты. <spoiler summary="Результаты прошлых лет"> [2025](https://mirror.codeforces.com/blog/entry/140577) [2024](https://mirror.codeforces.com/blog/entry/127605) [2023](https://mirror.codeforces.com/blog/entry/114266) [2022](https://mirror.codeforces.com/blog/entry/102044) [2021](https://mirror.codeforces.com/blog/entry/90111) [2020](https://mirror.codeforces.com/blog/entry/80808) [2019](https://scoreboard.bc-pf.org/results/informatics/national-olympiad/2019) [2018](https://scoreboard.bc-pf.org/results/informatics/national-olympiad/2018) [2017](https://scoreboard.bc-pf.org/results/informatics/national-olympiad/2017) </spoiler> #### **9 класс** | **Место** | **ФИО** | **CF handle** | **1 тур** | **2 тур** | **Общий** | **Медаль** | |---|---|---| | 1 | Бауыржан Шөкей | [user:Shad_29, 2025-08-27] | 234 | 143 | 377 |  | | 2 | Алишер Еламан | [user:Alish_1_2100,2026-03-22] | 203 | 135 | 338 | ![ ](https://codef...

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Need help in a math problem. Hi, In this [problem](http://mirror.codeforces.com/contest/185/problem/B), I am using the idea that AM >= GM just like in the editorial but with slightly different steps. ${x^a}{y^b}{z^c} \leq {(\frac{{ax}+{by}+{cz}}{a+b+c})}^{a+b+c}$ Equality should hold when all elements are equal. So according to me, $x = y = z$ and the solution I arrive at is that $x = y = z = S/3$ But this is incorrect as seen from the test case $S = 10$ $a = 1, b = 6, c = 3$ My solution gives $x = y = z = 3.33$ and hence $x^a\cdoty^b\cdotz^c=$ 169350.87 But the optimal solution is $x = 1.0, y = 6.0, z = 3.0$ with $x^a\cdoty^b\cdotz^c=$ 1259712 What is the flaw in my math? Is this not a correct way to use GM <= AM? I don't understand why my solution differs from the solution given in the editorial even though the principle behind both is the same.

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Республиканская олимпиада 2020 года. Казахcтан. Результаты. ####9 Класс <html> <body> <style type="text/css"> .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-0pky{border-color:inherit;text-align:left;vertical-align:top} </style> <table class="tg" style="undefined;table-layout: fixed; width: 579px"> <colgroup> <col style="width: 50px"> <col style="width: 160px"> <col style="width: 170px"> <col style="width: 97px"> <col style="width: 102px"> </colgroup> <thead> <tr> <th class="tg-0pky">Место</th> <th class="tg-0pky">ФИО</th> <th class="tg-0pky">CF handle</th> <th class="tg-0pky">Балл</th> <th class="tg-0pky">Медаль</th> </tr> </thead> <tbody> <...

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Codeforces Global Rounds 2020: Current Results (GR7-GR10) In 2020 (as 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 problem authors and problem testers.</i> 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 sweatshirts and place certificates. Current standings after four rounds (sorted by total points in four rounds): | Place | Contestant | = | GR 7 | GR 8 | GR 9 | GR 10| |--|--|--|--|--...

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WA in Problem based on Ternary search. HELP!! I am trying to solve [this](http://mirror.codeforces.com/problemset/problem/185/B) problem using ternary search. It asks to find the maximum of the function x^a·y^b·z^c. Where, x+y+z <= S. I submitted the following solution which is giving WA. [link](http://mirror.codeforces.com/contest/186/submission/18289965) However, [this](http://mirror.codeforces.com/contest/186/submission/1656097) AC solution is very similar. Can somebody help ?

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Country statistics Hi guys! I have prepared for you some statistics on how countries are performing against each other in Codeforces which I hope you will find interesting! ## Top 5 countries with the most users with certain rank:  ## Top 5 countries with highest percentage of their users in a certain rank: (Here I don't count countries that have less than 10 Codeforces users)  #### Newbie:  #### Pupil:  #### Specialist:  #### Expert:  #### Candidate Master:  #### Master: ![ ](/pre...

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Teams Going to ECPC (Egyptian Collegiate Programming Contest) 2019 ### Teams Going to ECPC (Egyptian Collegiate Programming Contest) 2019 Hello, Since ECPC is only 4 Days apart, I thought it was time for teams participating in the contest to know each other. So please if your team is going to participate in ECPC 2019. leave your team name, your university name, as well as the handles of the team members in a comment. I'll try to update this blog frequently. I think it's fun to get to know the participants as well as the exquisite team names :D. and I will sort them according to Codeforces Rating , using this Formula [Rating for Teams](https://mirror.codeforces.com/blog/entry/16986) See you there and good luck <3 <3 <table> <tr style = "background-color: rgb(185, 185, 185);"> <td><b> Rank </b></td> <td><b> Team Name</b></td> <td><b>University</b></td> <td><b>Team Members</b></td> <td><b>Codeforces Rating</b></td> </tr> <tr> <td><b>1</b> </td> <td><b>Compilation Error missing 'slifer'</b> </td> ...

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Codeforces Popularity Ranking Hello Codeforces! There has been several blogs similar to this. I know about [TOP 15 most popular users on codeforces](http://mirror.codeforces.com/blog/entry/49122) and [Who is the most popular?](http://mirror.codeforces.com/blog/entry/21041). But as none of these are updated, I thought this might be helpful. I have just calculated the most popular handles in Codeforces. I only considered those handles which have at least one rated contest. Begging my pardon to them who hasn't participated in any rated round. And here, the popularity depends simply on the number of people you are friend of. The complete standings can be found [here](https://docs.google.com/spreadsheets/d/1ADlF-bd6pBYCap75yzf-pUnVwI9f9YmPkiYNW3lD-xo/edit?usp=sharing)(This may took a while to load at the bottom). Anyway here is Top 200 handles. | Rank | Handle | Follower | |---|---|---| 1. | [user:tourist,2018-08-22] | 14082 | 2. | [user:Petr,2018-08-22] | 6430 | 3. | [user:OO0OOO00O0OOO0O00OOO0OO,2018-08-22] | 420...

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Who participated most? **UPD:** The calculation updated, for some reason I filtered only CF style competitions. Now it includes everything. Still [user:ruban,2024-08-07] best :) I revisited some data from Codeforces and, [after 5 years](https://mirror.codeforces.com/blog/entry/72410), decided to calculate again who has participated in the most contests. I took into account all official contest participations, including those where a user participated unofficially. However, I excluded Practice/Virtual contests. P.S: I think no one will beat [user:ruban,2024-08-07] ever :) |Rank|Handle|Total|Official|Unofficial| |---|---|---|---|---| | 1 |  [user:ruban,2024-08-13] | 1164 | 1090 | 74 | | 2 |  [user:kmjp,2024-08-13] | 972 | 547 | 425 | | 3 |  [user:dreamoon_love_AA,2024-08-13] | 891 | 538 | 353 | | 4 | ![ ](https://mirror.codeforces.com/codeforces.org/s...

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185 E Soap Time! — 2 http://mirror.codeforces.com/contest/185/problem/E problem description doesn't mention what to output when there is no solution: for example: 2 0 1 0 2 0 what's the output to this samples?? 0.5 or 1 or no solution.. problem description doesn't mention it at all...

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Problems that I authored so far Since competitive programming is dying, and I'm almost retired, so it's time to review the problems I authored. Hi everyone! I wanted to write such a blog for a long time, motivated by similar blogs, [by](https://mirror.codeforces.com/blog/entry/113093) [user:antontrygubO_o,2023-02-25], [by](https://mirror.codeforces.com/blog/entry/108940) [user:adamant,2023-02-25] and [by](https://mirror.codeforces.com/blog/entry/108595) [user:tibinyte,2023-02-25]. This is not a super-comprehensive list. I set many shit problems that I don't want to share for some local contests. It can be long, and I'm not sure if I have finished half of them yet. The number of asterisks after the label indicates the recommendation levels. One asterisk means this problem is worth reading. Two asterisks mean this problem is one of my favorite problems, Three asterisks mean this problem is one of my best problems. | # | Date | Problem | Contest | Comment | | ---- | ----------- | --------------------------------------------...

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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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Что за ерунда с чекером? http://mirror.codeforces.com/contest/185/submission/1656438 --- что это такое?! Погрешность идет в восьмом знаке. Почему в чекере проверка на <= выполняется без эпсилона?

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Результаты Республиканской Олимпиады по Информатике 2025 ` Это результаты республиканской олимпиады по информатике 2025 Kazakhstan <spoiler summary="Результаты прошлых лет"> [2024](https://mirror.codeforces.com/blog/entry/127605) [2023](https://mirror.codeforces.com/blog/entry/114266) [2022](https://mirror.codeforces.com/blog/entry/102044) [2021](https://mirror.codeforces.com/blog/entry/90111) [2020](https://mirror.codeforces.com/blog/entry/80808) [2019](https://scoreboard.bc-pf.org/results/informatics/national-olympiad/2019) [2018](https://scoreboard.bc-pf.org/results/informatics/national-olympiad/2018) [2017](https://scoreboard.bc-pf.org/results/informatics/national-olympiad/2017) </spoiler> 9 класс ----------- <table> <thead> <tr> <th>Место</th> <th>ФИО</th> <th>CF handle</th> <th>1 тур</th> <th>2 тур</th> <th>общий</th> <th>Медаль</th> </tr> </thead> <tr> <td> 1 </td> <td> Даужан Бекетов </td> <td> [user:Away_in_the_heavens,2025-03-12] </td> <td> 196 </td> <td> 173 </td> <td> 369 </td> <td> <img alt=" " src="/predownloaded/93/7...

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Codeforces Global Rounds 2019: Current Results 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 two rounds: | Place | Contestant | = | Round 1 | Round 2| | - | - | - | - | - | | 1 | [user:tourist,2019-06-01] | 1706 | 1000 | 706 | | 2 | [us...

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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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Я ПРОШЁЛ!!!!!!!!!! Конечно запоздал я с этой новостью, но лучше поздно чем никогда. По результатам 3 раунда я занял 185 место и прошёл в финал Технокубка!!! Когда будет сам финал я не знаю, но попытаюсь к нему хорошо подготовится.

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codeforces.com error [see error](http://mirror.codeforces.com/problemset/status/185/problem/C/page/1000000999?order=BY_PROGRAM_LENGTH_ASC)

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Республиканская олимпиада 2022 год. Казахстан 2021 : https://mirror.codeforces.com/blog/entry/90111 2020 : https://mirror.codeforces.com/blog/entry/80808 2019 : https://scoreboard.bc-pf.org/results/informatics/national-olympiad/2019 2018 : https://mirror.codeforces.com/blog/entry/58432 2017 : https://mirror.codeforces.com/blog/entry/51416 #### 9 класс <table> <thead> <tr> <th>Место</th> <th>ФИО</th> <th>CF handle</th> <th>Балл</th> <th>Медаль</th> </tr> </thead> <tr> <td>1 </td><td>Таймас Мансур</td><td>[user:gamicrab,2022-04-19]</td><td>322</td></td><td><img alt=" " src="/predownloaded/93/73/9373156f429b185ba6bc779f81d16894f9a72d9e.png" style="max-width: 100.0%;max-height: 100.0%;"> </td> </tr> <tr> <td>2 </td><td>Абжами Ерсултан</td><td>[user:syrtin,2022-04-19]</td><td>274</td></td><td><img alt=" " src="/predownloaded/93/73/9373156f429b185ba6bc779f81d16894f9a72d9e.png" style="max-width: 100.0%;max-height: 100.0%;"> </td> </tr> <tr> <td>3 </td><td>Шермаханов Ильяс</td><td>[user:Tenjin,2...

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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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IOI 2025 Ranking Prediction Hello Codeforces! Less than a week to IOI 2025! I used accounts from [this blog](https://mirror.codeforces.com/blog/entry/142475) and made the **prediction** for the IOI 2025 ranking. Ratings are calculated based on the average of the current rating and the maximum rating. [cut] <table width="100%"> <thead> <tr> <th> Predicted Rank </th> <th> Actual Rank </th> <th> CF handle </th> <th> Name </th> <th> Country </th> <th> Rating </th> <th> Predicted Award </th> <th> Actual Award </th> </tr> </thead> <tbody> <tr style="background-color:#FFEE55;"> <td> 1 </td> <td> </td> <td> [user:JoesSR,2025-07-25] </td> <td> </td> <td> &#x1f1e8;&#x1f1f3; China </td> <td> 3163.0 </td> <td> &#x1f947; Gold </td> <td> </td> </tr> <tr style="background-color:#FFEE55;"> <td> 2 </t...

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Help for Codeforces Round #185(Div.2 B) Would anyone please give me a explanation on [problem:312B] ???

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Республиканская олимпиада 2018 года. Казахcтан. Результаты. Результаты республиканской олимпиады 2018 года (Казахстан). Это не весь список, полную версию вы можете посмотреть здесь <br> [Результаты](http://sportprog.io/). <br> Про результаты прошлого года можете почитать [здесь](http://mirror.codeforces.com/blog/entry/51416) <br> Если есть ошибки или вопросы обращайтесь в лс. <br> <br> 9 класс <br> <style type="text/css"> .tg {border-collapse:collapse;border-spacing:0;} .tg td{font-family:Arial, sans-serif;font-size:14px;padding:10px 5px;border-style:solid;border-width:1px;overflow:hidden;word-break:normal;} .tg th{font-family:Arial, sans-serif;font-size:14px;font-weight:normal;padding:10px 5px;border-style:solid;border-width:1px;overflow:hidden;word-break:normal;} .tg .tg-yw4l{vertical-align:top} </style> <table class="tg"> <tr> <th class="tg-yw4l">Место</th> <th class="tg-yw4l">Имя</th> <th class="tg-yw4l">Область</th> <th class="tg-yw4l">1 тур</th> <th class="tg-yw4l">2 тур</th> <th class="tg-yw4l...

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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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Milestones: ratings below 1500 and greatest rises (2024 edition) <i>Note.</i> This is an updated version of [this post](https://mirror.codeforces.com/blog/entry/104683). If you like [this style](https://mirror.codeforces.com/blog/entry/104320) more, please tell me in the comments. Since [user:tourist,2024-09-05]'s [breakthrough](https://mirror.codeforces.com/blog/entry/133401), I've received a lot of requests to update my old posts with rating achievements. However, I wasn't able to do it immediately since my method of doing it requires to download the rating change history of every user, which, in turn, requires to perform several hundred thousand requests to Codeforces, about which the website (and Cloudflare) is not happy. It took more that three days, but finally the job is done! Below are two tables. The first one is the greatest positive rating changes. The second one is the first users ever to reach some rating value. [cut] <table> <tr> <th>Place</th> <th>&Delta;</th> <th>Person</th> </tr> <tr> <td>1^st</td> <td><b>1182<...

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