Goodbye 74TrAkToR + Problem A~E: The problems themselves are good and typical A~E. Indeed I like problem D. The pretest for A is a bit weak, and it's not a big problem yet. + Problem F: The problem has an origin. :) See the link: [click](https://www.luogu.com.cn/problem/P9394). The problem in contest is only a weakened version of the one in Luogu. + Problem G: It's said that our great coordinator had not proved the time complexity of the intended solution is correct :) If the authors did, please share it in the editorial. (although this problem is completely beyond my ability :) ) + Problem H: Oh dear [user:74TrAkToR,2023-12-30], could you please OEIS the sequence before you use the "several-integer-input" problem in rounds next time? Anyone who copied the first example and opened [https://oeis.org/A286331](https://oeis.org/A286331) could quickly get the formula. And the problem itself is not so hard imo. Anyway, it should not be used in contest, especially for the last problem. For me pers...

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Codeforces Round #628 (Div.2) Hi! Codeforces round #628 (vintage Codeforces round #2) will take place on [contest_time:1325]. It's rated for the second division, but, as usual, first division participants can take part out of competition. The problems were created by me. I'd like to thank, and orz, [user:antontrygubO_o,2020-03-12] for coordinating the round; [user:ramchandra,2020-03-12], [user:pajenegod,2020-03-12], [user:aryanc403,2020-03-12], [user:Taran_1407,2020-03-12], [user:Kuroni,2020-03-12], [user:mcdx9524,2020-03-12], [user:dorijanlendvaj,2020-03-12], [user:Andreasyan,2020-03-12], [user:300iq,2020-03-12], [user:zoooma13,2020-03-12], [user:Osama_Alkhodairy,2020-03-12], [user:Mohammad_Yasser,2020-03-14], and [user:DeadPillow,2020-03-12] (special shout-out) for testing the round; and of course [user:MikeMirzayanov,2020-03-12] for the great codeforces and polygon platforms. You'll be given 6 problems and 2 hours to solve them. **UPD:** the scoring distribution will be 500-750-1250-1750-2500-2750. ...

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Codeforces round #628 editorial ### [problem:1325A] $a=1$ and $b=x-1$ always work. Code link: https://pastebin.com/ddHKD09B First AC: [user:Sevlll,2020-03-14] **Bonus task:** can you count the valid pairs? ### [problem:1325B] Let the number of distinct elements in $a$ be called $d$. Clearly, the answer is limited by $d$. Now, you can construct your subsequence as follows: take the smallest element from the first copy, the second smallest element from the second copy, and so on. Since there are enough copies to take every element, the answer is $d$. Code link: https://pastebin.com/hjcxUDmY First AC: [user:socho,2020-03-14] ### [problem:1325C] Notice that there will be a path that passes through the edge labeled $0$ and the edge labeled $1$ no matter how you label the edges, so there's always a path with $MEX$ $2$ or more. If any node has degree 3 or more, you can distribute the labels $0$, $1$, and $2$ to edges incident to this node and distribute the rest of the labels arbitrarily. Other...

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What happened to 1400+ Codeforces users from 2021 to now? I took every Codeforces user who (a) was rated **1400 or higher at some point in 2021** and (b) is **still competing** (active rated list, and at least one rated contest since 2025-01-01). That is **746 users**. I pulled their full rating histories from the public Codeforces API and measured the cohort at each major AI release that mattered for competitive programming. All numbers below come from `user.ratedList` and `user.rating`. Data was fetched on 2026-10-08. Charts and code are available on request. **Important caveat up front:** this post shows *what happened*. It does not show *why*. Rating trends have many causes, and I mark clearly where I'm speculating. ## How the cohort was built 1. `user.ratedList?activeOnly=true` returned 43,131 active rated users. 2. I kept those registered by the end of 2021 whose max rating is ≥ 1400: **1,600** candidates. 3. For each candidate I fetched `user.rating` and kept those whose rating was ≥ 1400 at any time in 2021 (including th...

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Introduction to Digit Dynamic Programming Hello Codeforces! This series of videos are focused on explaining dynamic programming by illustrating the application of digit DP through the use of selected problems from platforms like Codeforces, Codechef, SPOJ, CSES and Atcoder. After going through this series, you should find yourself confident in solving problems which require the use of digit dp and also implementing them in a reasonable amount of time. I will also live code and submit the solutions to the problem on the coding platform from where the problem comes. Some Basic elements of Dynamic Programming ------------------ Some general ideas and my thoughts about DP to help you get started:<br> Part 1: [https://youtu.be/24hk2qW_BCU](https://youtu.be/24hk2qW_BCU)<br> 1. What is Divide and Conquer?<br> 2. What is Dynamic Programming?<br> 3. Types of DP problems.<br> Part 2: [https://youtu.be/yfgKw6BUZUk](https://youtu.be/yfgKw6BUZUk)<br> 1. What is a DP-state?<br> 2. Characterizing a DP-state.<br>...

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Round #628 Video Solutions and Coaching I made video solutions to all the problems (A-F) of Round #628 which you can find in this playlist [here](https://www.youtube.com/playlist?list=PLTDB_sARFkANcjgcyUkrOR7_1UOwS_4vi) or using the links below. [Problems A and B](https://www.youtube.com/watch?v=NypbGDJzLqQ&list=PLTDB_sARFkANcjgcyUkrOR7_1UOwS_4vi&index=1) [Problem C](https://www.youtube.com/watch?v=esodAk_DDiw&list=PLTDB_sARFkANcjgcyUkrOR7_1UOwS_4vi&index=2) [Problem D](https://www.youtube.com/watch?v=Yb_cHZ67YPM&list=PLTDB_sARFkANcjgcyUkrOR7_1UOwS_4vi&index=3) [Problem E](https://www.youtube.com/watch?v=8QBSXGei06s&list=PLTDB_sARFkANcjgcyUkrOR7_1UOwS_4vi&index=4) [Problem F](https://www.youtube.com/watch?v=lCvprds-ZwM&list=PLTDB_sARFkANcjgcyUkrOR7_1UOwS_4vi&index=5) As a side note, with all my extra time from staying home, I'm coaching people who spend 6-10+ hours a week coding with targeted problems to improve rating. If you are interested, fill out [this form](https://docs.google.com/forms/d/e/1FAIpQLS...

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All Arpa's source code comments A fully comprehensive list of all of [user:Arpa,2019-01-08]'s various comments in his templates <spoiler summary="Click"> ~~~~~ // God & me // Lost l<3ve is back :P -:~:- // In the name of God. // You are all thing and We're nothing. // Ya Ali! -:~:- //ya mahdi adrekni -:~:- // God & me // Life is ruined and love is lost :'( // @Yazd -:~:- // God & me // Don't forget me, I beg -:~:- //God & me //Damned if AmirAz doesn't take what he wants. -:~:- // God & me // Life is ruined and love is lost :'( // @Yazd // Happy 1300 <3 -:~:- // God & me // Don't forget me ... -:~:- //God & me //..... ...... ..... .... <3 -:~:- // ya mahdi adrekni '-| //contest: To l<3ve m.sina or not to love; This is the problem! //Welcome to new series of "f*** this bloody contest tonight" (upsolving) -:~:- //God & me //Keep calm and go home ;) -:~:- //God & me -:~:- // God & me // I found myself in Love empire // The 1500'th accept ! -:~:- //God & me ...

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Need Help in resolving TLE in DP with memo and iterative. Why do some solutions containing dp with memoization result in TLE but the same iterative version always passes? I have had this doubt for quite a while. For example this problem : https://codeforces.me/contest/628/problem/D <spoiler summary="DP+Memo->TLE"> ~~~~~ #include <bits/stdc++.h> using namespace std; #define fast ios::sync_with_stdio(0); cin.tie(0); cout.tie(0); #define ll long long #define all(v) v.begin(),v.end() #define ff first #define ss second #define pb push_back #define mp make_pair #define pi pair<int,int> #define REP(i,n) for(int i=0;i<n;i++) const int N = 2e5+10; const ll mod = 1e9+7; int m,d; string a,b; int dp[2001][2][2001]; int solve(int pos,int f1,int rem,string x){ if(pos==(int)a.length()){ if((rem%m)==0) return 1; return 0; } if(dp[pos][f1][rem]!=-1) return dp[pos][f1][rem]; int ulmt; if(f1) ulmt=9; else ulmt=(x[pos]-'0'); int ans=0; for(int i=0;i<=ulmt;++i){ int nf1,nrem,nis; if(f1==...

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Codeforces Round #657 (Div. 2, по Всероссийской олимпиаде имени Келдыша) [Рейтинговый] Всем привет! В воскресенье состоится всероссийская олимпиада школьников для 5-8 классов имени Келдыша. Удачи всем участникам! Олимпиада проходит под чутким руководством московской методической комиссии в лице [user:GlebsHP,2020-07-17], [user:ch_egor,2020-07-17], [user:Endagorion,2020-07-17], [user:gritukan,2020-07-17], [user:Zlobober,2020-07-17], [user:_meshanya_,2020-07-17], [user:_kun_,2020-07-17], [user:voidmax,2020-07-17], [user:grphil,2018-07-17] и, конечно, Андреевой Елены Владимировны. Мы рады представить Codeforces Round #657 (Vintage Codeforces Round #3) на основе задач олимпиады. Это будет Div. 2 раунд, который состоится в [contest_time:1379]. Возможно, вы уже и раньше участвовали в раундах на основе олимпиад, подготовленных московской методической коммисией (раунды <a href="https://codeforces.me/blog/entry/21185">327</a>, <a href="https://codeforces.me/blog/entry/23309">342</a>, <a href="https://codeforces.me/blog/entry/43615">345</a>, <a href="https://codeforces.co...

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[Training] [Arabic] [JAVA] Al-Balqa' Problem Solving Training 2017 for Beginners Hello Codeforces, From January 2017 to April 2017 the BAU Problem Solving Beginners 2017 in Al-Balqa' Applied Univeristy Presented By Dr. Muath Al-Zghoul [user:mrrz75,2018-09-14] using JAVA and consists of 24 Lectures and its the first training recorded and published by [user:SolverToBe,2018-09-14]. *note: language of training is Arabic. #### **Lecture 2** <spoiler summary="Introduction"> [Problem Solving and Online Judges](https://www.youtube.com/watch?v=pRKIT6Wbrw8&list=PLPSFnlxEu99H9hv_oWXtkRSl7OdOc_0V5&index=1) </spoiler> #### **Lecture 3** <spoiler summary="Input/Output"> [Input/Output and Data Types](https://www.youtube.com/watch?v=4pnNyoQsZx4&list=PLPSFnlxEu99H9hv_oWXtkRSl7OdOc_0V5&index=2) </spoiler> #### **Lecture 4** <spoiler summary="Problem Roy and Profile Picture"> [Problem Roy and Profile Picture &mdash; Hackerearth](https://www.youtube.com/watch?v=Cs2hXspdQzk&list=PLPSFnlxEu99H9hv_oWXtkRSl7OdOc_0V5&index=3) </spoiler> #### **Lecture 5** ...

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Digit DP Wrote this article a long ago but during solving a problem recently thought of sharing this article publicly. Hope it will help some contestants to understand the idea clearly. Digit dp is a very easy technique and also useful to solve many dynamic programming problems. Seeing the name “Digit DP” it’s easy to guess that we are going to do something using the digits. Yes we are actually going to play with digits. Let’s explain the concept using a classical problem. #### Problem How many numbers **x** are there in the range **a** to **b**, where the digit **d** occurs exactly **k** times in **x**? There may have several solutions including number theory or combinatorics, but let’s see how we can solve this problem using digit dp. #### Solve for range (zero to a) Using digit dp we always focus on building a number satisfying all the conditions. If we finally manage to build that number then we say, yes we have got one ;-) But how we’ll build that number? For the time being let...

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TCO 2011, days 2 and 3 <p>TopCoder Open 2011 keeps going.<br /><br />Yesterday we were supposed to hold a poker tournament with a grand prize MacBook Air. There were a lot of people willing to participate, which forced us to split the tournament into two elimination rounds and one final. Out of 16 people who registered for the tournament, 8 were russian-speaking, and all of them appeared to be in the same elimination round. Petr and MikhaelOK advanced from that round, while 7ania7 and theycallhimtom advanced from another one, which was non-russian-speaking. Unfortunately I don't have any pictures of the elimination rounds, however, we played more poker that day, in the same place, so this picture gives you pretty good understanding of how it looked like (during the elimination round it was a little bit more crowded though):<br /> <span> <img alt="" border="0" height="449" src="http://content.foto.mail.ru/bk/shd/_blogs/i-626.jpg" width="600" /> </span> <br /><br />Last time I didn't publi...

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TopCoder SRM 629 — Long time with no SRMs Tomorrow, SRM 629 will be held at [11:00 EDT](http://www.timeanddate.com/worldclock/fixedtime.html?&day=12&month=08&year=2014&hour=11&min=00&sec=0&p1=179). This SRM is 3 weeks after the previous one (SRM 628 was on Jul 22, my birthday :D ). 3 weeks without TopCoder (except TCO14 Round 3), I'm sure that many people and I miss TopCoder too much! A sad fact that the number of SRMs is decreasing recently. After some months with 4 SRMs each, July has only 2, August has 3, and it's still not sure about next months. I don't know the reason, but it will be a great pity if there aren't any more SRMs. I like some SRM rules. The one I like most is that the ratings will change if we open a problem. This forces us to try our best to solve problems, or our ratings will decrease much (we can't keep our ratings unchange by not making any submissions). The next one is value of a problem starts decreasing when we open it (not from the beginning of the contests). We don't have to choose which problem ...

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[Help] Finding the DP state in problem and Initialising the base cases The question I am asking is very vague but if some experts can share some of their tricks or tips while solving DP questions would be really helpful. The problems I face is how to think of such complex DP states, and even if I think of them, how should I initialse the base values(e.g $dp[0][0] = 1 or 0$). Consider the two problems 1. [D. Magic Numbers](http://codeforces.me/contest/628/problem/D) 2. [B. Numbers](http://codeforces.me/contest/213/problem/B) Both of them have DP based solutions. **D.Magic Numbers** [Tutorial link](http://codeforces.me/blog/entry/43203) Brief Solution: $dp[i][j][k]$ is our dp state that represents number of magic prefixes of length $i$ with remainder $j$ modulo $m$. If $k = 0$ than the prefix should be less than the corresponding prefix in $n$ and if $k = 1$ then the prefix should be equal to the prefix of $n$ (it can not be greater). First of all, how does one realises the need of having that $[k]$ in out DP. Also in the [solution...

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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://codeforces.me/blog/entry/49122) and [Who is the most popular?](http://codeforces.me/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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KEP Contest #9  I invite everyone to the [contest](https://kep.uz/competitions/contests/contest/406), which will take place on **October 27, 2024 at 9:00UTC**. Interesting problems await you in the contest. **Contest info:** - Number of problems: **10** - Difficulty of problems: **< 2400** - Duration: **3 hours** - Contest type: **ACM20M** - Languages: **C++, Python, C, Kotlin, Haskell, R, Nodejs, PHP, C#, Java, Rust** **Prizes:** - First place – **25$ (USDT)** - Second place – **20$** - Third place – **15$** - Fouth place – **12.5$** - Fifth place – **10$** Link to the platform: https://kep.uz/competitions/contests/ P.S. Registration on the platform only via Gmail/Github. **UPD** Thank you for participating **Results** 1. [user:vtb,2024-10-27] &mdash; 10 (628) 2. [user:JahonaliX,2024-10-27] &mdash; 9 (376) 3. [user:Lucina,2024-10-27] &mdash; 9 (953) 4. [user:Timosh,2024-...

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The story behind "Limak , the little polar bear" Hello everybody Everyone are wondering about the story behind "Limak , the little polar bear". Too many statements talking about Limak , [here](http://codeforces.me/problemset/problem/611/A) , [here](http://codeforces.me/problemset/problem/628/C) , [here](http://codeforces.me/problemset/problem/679/B) and even on [CodeChef](http://codeforces.me/blog/entry/50614) So would anyone tell us about the story behind this famous polar bear

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Help with Digit Dp problem (Magic Numbers) I was attempting this problem : https://codeforces.me/contest/628/problem/D and came up with a solution which basically look like this : ~~~~~ int d, m; ll int magicNumberDP(string n, int idx,ll int curNum, bool tight) { if (idx >= n.length()) { return !curNum ; } int uprBnd = (tight) ? n[idx] - '0' : 9 ; ll int ans = 0 ; for (int dig = 0 ; dig <= uprBnd ; dig++) { if ((idx + 1) % 2 == 0 and d != dig) { continue ; } if ((idx + 1) % 2 == 1 and d == dig) { continue ; } ans = ans + magicNumberDP(n, idx + 1, (curNum * 10 + dig) % m, tight & (dig == uprBnd)) ; } return ans; } void magicNumber() { cin >> m >> d ; ll int r, l; cin >> l >> r ; l--; string R = to_string(r); string L = to_string(l); int ansR = magicNumberDP(R, 0, 0ll, 1); int ansL = magicNumberDP(L, 0, 0ll, 1); cout << ansL << " " << ansR << endl ; cout << ansR - ansL << endl; } ~~~~~ But this is giving wrong answer can someone tel...

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Betlista's TopCoder SRM 648 editorial In SRM there were 1303 registered participants [cut] - DIV1 562, DIV2 628 + 113 newcomers ### DIV2 — easy (250) Ona have to return the length of binary number T/K without the zeros at the beginning. ### DIV2 — medium (500) Greedy &mdash; check, whether after pair removal, the number of components is increased, if so, remove the pair. Return the number of such pairs. ### DIV2 — hard (1000) Inspired by hippie (room 61). DP: We can calculate for each AC, BC and CC (A count, B count, ...) and PC (Pair Count), whether it is possible or not. Once we know it is possible, we can run the same algorithm, to find the string. ### DIV1 — easy (250) Same as DIV2 hard, but with only two characters instaed of three. **Note:** as always I will write more detailed descripton a little later...

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Tracking Codeforces Educational Rounds - Educational Codeforces Round 1 (http://codeforces.me/contest/598) - Educational Codeforces Round 2 (http://codeforces.me/contest/600) - Educational Codeforces Round 3 (http://codeforces.me/contest/609) - Educational Codeforces Round 4 (http://codeforces.me/contest/612) - Educational Codeforces Round 5 (http://codeforces.me/contest/616) - Educational Codeforces Round 6 (http://codeforces.me/contest/620) - Educational Codeforces Round 7 (http://codeforces.me/contest/622) - Educational Codeforces Round 8 (http://codeforces.me/contest/628) - Educational Codeforces Round 9 (http://codeforces.me/contest/632) - Educational Codeforces Round 10 (http://codeforces.me/contest/652) - Educational Codeforces Round 11 (http://codeforces.me/contest/660) - Educational Codeforces Round 12 (http://codeforces.me/contest/665) - Educational Codeforces Round 13 (https://codeforces.me/contest/678) - Educational Codeforces Round 14 (https://codeforces.me/contest/691) - Educational...

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iterative code running slower than recursive. Why ? I tried solving problem [magic numbers](https://codeforces.me/contest/628/problem/D) with iterative digit dp. But it runs slower than my recursive solution by more than 200ms. iterative : [link](https://codeforces.me/problemset/submission/628/127908284) recursive : [link](https://codeforces.me/problemset/submission/628/127908296) I also avoided using modulo operations in my iterative code, but am surprised to see it running slower. Any idea why this happened?

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Variation of Topcoder SRM 628 Div1 500 "CircuitsConstruction" Topcoder SRM 628 had a fairly easy (compared to Div1 500 of other SRM's) Div 1 500 pointer named CircuitsConstruction .(http://community.topcoder.com/stat?c=problem_statement&pm=13237). But what if we change the problem to finding the minimum possible resistance of the constructed circuit( Instead of largest). This turns the problem to a more difficult one because the type-B connection is resulting into the maximum resistance of the two circuits. Is the new problem is even solvable other than brute force ?

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(ReView) Gấu em là hot girl................................................................... - conglb Các thím cứ xem đây là một câu truyện nhé , vì không muốn ảnh hưởng tới cuộc sống của em và gấu nên một số info em đã thay đổi, hi vọng các thím đừng lùng info của em ! Chúc các thím có những giây phút hạnh phúc bên gia đình và người thân ! Chap 1 : Chào các thím trong Voz , em biết tới voz khá lâu, toàn vào đọc truyện của các thím thôi nên hôm nay quyết định viết đôi dòng tâm sự mà cũng có thể nói là một câu truyện về cuộc đời e ( tin hay không tùy các thím, cứ coi nó là câu truyện để đọc , để cảm nhận và để biết cuộc sống muôn màu nhé ) . Hi vọng các thím hết lòng ủng hộ em, văn em dốt nên có chỗ nào không ổn các thím thông cảm nhé. Với trong lòng đang vui vì hồi chiều chen lấn cũng mua được cặp vé xem U19 Việt Nam đá, may chiều nay mua chứ mai chắc là hết cmnr. Chỉ đợi gấu đi công tác về, cuối tuần sau 2 đứa đi xem đá bóng, đây là lần đâu tiên em xem trực tiếp tại Mỹ Đình, không biết có vui hông ? À giới thiệu qua với các thím , em là sinh viên năm cuối ở một trường ĐH ở...

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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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IOI 2022 Country Standings Hello everyone! Similar to [last year](https://codeforces.me/blog/entry/92631), these are the country standings for IOI 2022 based on the sum of scores of all contestants. Check the spoiler at the bottom for the complete list. <table style="width:100%"> <tr> <th>Rank</th> <th>Team</th> <th>Score</th> </tr> <tr> <td>1</td><td>CHN</td><td>2310 </td></tr> <tr> <td>2</td><td>USA</td><td>1909 </td></tr> <tr> <td>3</td><td>JPN</td><td>1871 </td></tr> <tr> <td>4</td><td>IOI_2</td><td>1725 </td></tr> <tr> <td>5</td><td>KOR</td><td>1624 </td></tr> <tr> <td>6</td><td>CAN</td><td>1504 </td></tr> <tr> <td>7</td><td>TWN</td><td>1502 </td></tr> <tr> <td>8</td><td>UKR</td><td>1500 </td></tr> <tr> <td>9</td><td>IRN</td><td>1448 </td></tr> <tr> <td>10</td><td>ROU</td><td>1387 </td></tr> </table> <spoiler summary="Complete list"> <table style="width:100%"> <tr> <th>Rank</th> <th>Team</th> <th>Score</th> </tr> <tr> <td>1</td><td>CHN</td><td>2...

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Educationals Rounds Link (From Starting) I saw on Codeforces on a regular basis, that there are a lot of questions and answers about practicing and practicing more. Although It is my opinion that the Educationals Rounds are best for this, at least for people like me. They learn from it and the problems are very nice and interesting. There are many Educationals Rounds will come and I will also try my best to keep this blog update. Although if you want to generate these links <s>at any time</s> locally you can find the code on my GitHub repo: https://github.com/adshin21/Codeforces-Contest-Selector-By-Div-s So I've collected the links for all the educationals rounds that has happened. <table class = "bordertable" align="center"> <tbody> <tr> <td>Educational Round 1 </td> <td> <a href= " http://codeforces.me/contest/598" >http://codeforces.me/contest/598</a></td> <tr> <tr> <td>Educational Round 2 </td> <td> <a href= " http://codeforces.me/contest/600" >http://codeforces.me/contest/600</a></td> <tr> <tr> ...

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Разница между с++ и pascal Добрый день, уважаемое сообщество codeforces. Буквально пару недель назад я начал изучать с++, т.к. в этом году закончил школу. До этого я знал исключительно pascal и на всех олимпиадах кодил только на нем. Но при решении [этой](http://acmp.ru/index.asp?main=task&id_task=628) задачи я столкнулся с одной проблемой. Код на pascal получает Accepted, а на c++ Wrong Answer. Код на pascal: [тут](http://ideone.com/hrY8tv) Код на с++: [тут](http://ideone.com/7phCIw) И теперь я прошу тех, кто знает в чем причина Wrong Answer, рассказать её и как бороться с этой проблемой. Буду очень признателен!

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All DIV 3 contests links for practice Hello friends I am sharing the link of all div 3 links for practice. -------------------------------------------------------------------- <br><br> Div3 1: https://codeforces.me/contest/977<br> Div3 2: https://codeforces.me/contest/978<br> Div3 3: https://codeforces.me/contest/988<br> Div3 4: https://codeforces.me/contest/999<br> Div3 5: https://codeforces.me/contest/1003<br> Div3 6: https://codeforces.me/contest/1005<br> Div3 7: https://codeforces.me/contest/1006<br> Div3 8: https://codeforces.me/contest/1015<br> Div3 9: https://codeforces.me/contest/1029<br> Div3 10: https://codeforces.me/contest/1066<br> Div3 11: https://codeforces.me/contest/1077<br> Div3 12: https://codeforces.me/contest/1092<br> Div3 13: https://codeforces.me/contest/1095<br> Div3 14: https://codeforces.me/contest/1102<br> Div3 15: https://codeforces.me/contest/1108<br> Div3 16: https://codeforces.me/contest/1118<br> Div3 17: https://codeforces.me/contest/113...

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TopCoder SRM 628 It seems corresponding thread was not created by anybody else... How to solve 1000?

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Codeforces rating distribution over time I was curious about rating inflation, so I generated a json object containing counts and percentiles and some plots of codeforces rating distribution over months, only counting active contestants: <spoiler summary="Json object"> ``` { "2015-01-01": { "Active": { "count": 21827, "percentile": 0.0 }, "Expert+": { "count": 6763, "percentile": 69.01543959316443 }, "CM+": { "count": 1778, "percentile": 91.85412562422688 }, "M+": { "count": 724, "percentile": 96.68300728455583 }, "IM+": { "count": 236, "percentile": 98.91877033032483 }, "GM+": { "count": 124, "percentile": 99.43189627525541 }, "IGM+": { "count": 21, "percentile": 99.90378888532551 }, "LGM": { ...

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Поправочные коэффициенты и инфляция рейтинга <P>Результат последнего контеста оказался для меня довольно неожиданным, поэтому я решил собрать немного больше информации о возможностях изменения рейтинга CF. Если профиль участника позволяет наблюдать историю изменения&nbsp;его рейтинга, то у меня получились "профили контестов", в которых отражены рост или падение каждого участника конкретного соревнования.<BR>[cut]<BR><A href="http://codeforces.me/blog/entry/102">Формула расчёта&nbsp;рейтинга Codeforces</A> подразумевает сохранение суммы очков всех участников до и после раунда за счёт поправочных коэффициентов. На основании же обработанной мной информации получилась такая табличка:</P> <TABLE style="WIDTH: 100%" border=1> <TBODY> <COLGROUP> <COL width="20%"> <COL width="20%"> <COL width="20%"> <COL width="20%"> <COL width="20%"> <TBODY> <TR> <TD>ID контеста</TD> <TD>Суммарный рейтинг до соревнования</TD> <TD>Суммарный рейтинг после соревнования</TD> <TD>Разность конечного и исходного суммарных рейтингов</TD> <TD>Коли...

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