What if tourist goes rainboy mode? (Simulation) DISCLAIMER: NO TOURISTS AND RAINBOYS WERE PINGED Ah yes, two names that most people on Codeforces have heard -- <b>t<span style="color:red;">ourist</span></b> and <b><span style="color:purple;">rainboy</span></b>, one known as the CP Legend, and one as the user who does everything reverse. Such a great idea to put them together &mdash; a hypothetical user with the same ability as <b>t<span style="color:red;">ourist</span></b>, and solves problems the <b><span style="color:purple;">rainboy</span></b> way. _For those unaware of the "rainboy way", it means solving the problems in reverse order. In particular, if he cannot solve the final problem, he solves no problems in the contest._ Unfortunately, <b><span style="color:purple;">rainboy</span></b> had not yet reached red, peaking at 2398 rating. How far can this user go? We shall simulate this user through all the contests that tourist and rainboy took part in comparably, which adds up to 60 contests from [contest:745] to [cont...

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Our heroes: participants of four Codeforces rounds in two days Hello! Recently, Codeforces hosted 4 rounds in two days &mdash; [388](http://codeforces.me/contest/749/standings), [387](http://codeforces.me/contest/747/standings), [386](http://codeforces.me/contest/746/standings), 385 [Div 1](http://codeforces.me/contest/744/standings)/[Div 2](http://codeforces.me/contest/745/standings). Usually pauses between rounds are much large. This time, three of the four rounds were based on the onsite contests in Saratov and Samara, so the date of the rounds were attached to these events. I've prepared some interesting statistics: 450 people participated in each round and solved at least one problem in each of them. Wow! We did not expect it would be so much less enthusiastic participants. So happy! :) And here is a list of our heroes (found yourself?): [user:kakajapan31,2016-12-22], [user:butcherofblaviken,2016-12-22], [user:Bekzhan.Kassenov,2016-12-22], [user:3agwa,2016-12-22], [user:-Djok,2016-12-22], [user:vaibhavjaimini,201...

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Codeforces Round #388 (Div. 2) Всем привет! [В понедельник, 19 декабря в 19:35 MSK](https://www.timeanddate.com/worldclock/fixedtime.html?msg=Codeforces+Round+%23388+%28Div.2%29&iso=20161219T1635&p1=%3A&ah=2) состоится Codeforces Round #388 для участников из второго дивизиона. Участники из первого дивизиона могут принять участие вне конкурса. Для вас раунд готовили: Денис [user:pitfall, 2016-12-19] Безруков, Алексей [user:dalex,2016-12-19] Дергунов, Вячеслав [user:Slamur,2016-12-19] Муравьев, Егор [user:Petruchcho, 2016-12-19] Пономарев, Павел [user:craus, 2016-12-19] Семушин и Андрей [user:Shlakoblock, 2016-12-19] Гайдель. Для меня, [user:Slamur,2016-12-19] и [user:Petruchcho, 2016-12-19] это первый рейтинговый раунд. Надеемся, что все пройдет хорошо и каждый участник найдет для себя интересные задачи. Выражаем благодарность Глебу [user:GlebsHP, 2016-12-19] Евстропову за помощь в подготовке раунда и Михаилу [user:MikeMirzayanov, 2016-12-19] Мирзаянову за системы Polygon и Codeforces. **UPD:** Вам ...

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Constructive Algorithms: Binary & Fibonacci # Fixed Value Construction: Binary & Fibonacci *Translated to English using AI. For a better reading experience, please visit: [https://dk-qwq.github.io/blog/posts/bin-fib-decomposition/](https://dk-qwq.github.io/blog/posts/bin-fib-decomposition/)* ## Core Idea: Base Graph + Regulator Regardless of the fixed-value construction method used, the essence is to construct a logarithmic-level base, and then use a regulator to construct the target fixed value through splitting methods similar to binary or Fibonacci. --- ## 1. Binary Decomposition ### 1. Principle Overview By observing the value function, construct a base graph of the form $f_i = 2 \times f_{i - 1}$, obtaining $f_i = 2^i$. Perform a binary decomposition on the required fixed value, and finally achieve the construction of the fixed value through the regulator. ### 2. Practice Problems #### [Codeforces 388B &mdash; Fox and Minimal path](https://codeforces.me/problemset/problem/388/B) **Problem Stat...

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Codeforces Round #228 Statistics [contest:388] and [contest:389] round statistics [cut] : ### Div. 1 #### First accepted: **A** (00:02) [user:Petr,2014-02-03] <br/> **B** (00:10) [user:Dmitry_Egorov,2014-02-03] [user:Petr,2014-02-03] <br/> **C** (00:13) [user:EmK,2014-02-03] <br/> **D** (00:37) [user:rng_58,2014-02-03] <br/> #### Total hack attempts: +252:-197 #### Top-5 hackers: **1000** [user:Monyura,2014-02-03] +11:-2 <br/> **900** [user:tncks0121,2014-02-03] +9:-0 <br/> **850** [user:poopi,2014-02-03] +11:-5 <br/> **850** [user:Sfairat,2014-02-03] +10:-3 <br/> **650** [user:gridnevvvit,2014-02-03] +7:-1 <br/> #### Other info [FAQ](/blog/entry/10150) <br/>  <br/>  <br/> ![ ](https://lh4.googleusercontent.com/-BM7rDheDJFM/UvBxqbD2API/AAAAAAAABSI/lTW--Ry4Jo4/s0/CF_228_1...

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BEST BOOKS FOR COMPETITIVE PROGRAMMING _These are the best of all books available, for mastering Competitive Programming:_ 1. **Competitive Programming 3: The New Lower Bound of Programming Contests** Book by Felix Halim and Steven Halim, 423 pages. 2. **Guide to Competitive Programming: Learning and Improving Algorithms Through Contests** A textbook by Antti Laaksonen, 286 pages. 3. **Programming Challenges** Book by Steven Skiena, 376 pages. 4. **Introduction to Algorithms** Book by Thomas H. Cormen, Charles E. Leiserson, Ronald Rivest, and Clifford Stein, 1216 pages. 5. **The Algorithm Design Manual** A textbook by Steven Skiena, 742 pages. 6. **Concrete Mathematics** A textbook by Donald Knuth, Oren Patashnik, and Ronald Graham, 648 pages. 7. **Cracking the Coding Interview** Book by Gayle Laakmann McDowell, 696 pages. 8. **Computational Geometry: Algorithms and Applications** A textbook by Marc van Kreveld, Mark de Berg, and Otfried Cheong, 388 pages. 9. **Estructuras de Datos...

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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://codeforces.me/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://codeforces.me/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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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://codeforces.me/problemset/status/1/problem/A) [1B](http://codeforces.me/problemset/status/1/problem/B) [1C](http://codeforces.me/problemset/status/1/problem/C) [2A](http://codeforces.me/problemset/status/2/problem/A) [2B](http://codeforces.me/problemset/status/2/problem/B) [2C](http://codeforces.me/problemset/status/2/problem/C) [3A](http://codeforces.me/problemset/status/3/problem/A) [3B](http://codeforces.me/problemset/status/3/problem/B) [3C](http://codeforces.me/problemset/status/3/problem/C) [3D](http://codeforces.me/problemset/status/3/problem/D) [4A](http://codeforces.me/problemset/status/4/problem/A) [4B](http://codeforces.me/problemset/status/4/problem/B) [4C](http://codeforces.me/problemset/status/4/problem/C) [4D](http://codeforces.me/problemset/status/4/problem/D)...

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I reached top 100 contributors without posting a blog Yes you read the title right. I reached top 100 contributors without posting a blog. and it wasn't for my comments to! So you may ask how I achieved such a great accomplishment? Everything started about a year ago. The day I forgot to log out of the school computer and someone wrote a blog with my account and got a lot of contribution (308 as I am writing this blog). you can read it [here](https://codeforces.me/blog/entry/108962). Then about 4 month ago one of my friends ([user:arash.,2024-02-08]) wrote my second blog but it didn't get much contribution (86 as I am writing this blog). you can read it [here](https://codeforces.me/blog/entry/122146). And about 2 month ago another friend of mine ([user:Aliish,2024-02-08]) wrote a blog to congratulate [user:alireza_kaviani,2024-02-08] for becoming the first Iranian LGM and I asked him to let me post the blog and he agreed. it got a lot of contribution (388 as I am writing this blog). and you can see the blog [here](htt...

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HHKB Programming Contest 2025(AtCoder Beginner Contest 388) Announcement We will hold HHKB Programming Contest 2025(AtCoder Beginner Contest 388). - Contest URL: https://atcoder.jp/contests/abc388 - Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20250111T2100&p1=248 - Duration: 100 minutes - Writer: MMNMM, [user:cn449,2025-01-10], [user:physics0523,2025-01-10] - Tester: [user:sotanishy,2025-01-10], [user:toam,2025-01-10] - Rated range: ~ 1999 - The point values: 100-200-300-400-450-550-575 We are looking forward to your participation!

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Hack me! — Year 2014 in review! (part 2.) Merry Christmas everyone! One round behind us, one more to go in this year. It's time for the second part of my little summing-up (last post can be found [here](/blog/entry/15326)). Now we will show all most accurate hackers. We will count the accuracy as the: $$\frac{\#successfulhacks}{\#allhacks}$$ Because there were a lot of flawless hackers, below we show only hackers with at least 10 successful hacks &mdash; still there were 36 of them! The full list of hackers' accuracy can be found [here](http://test.weaselcrow.com/pro/cf/ahack2014/). Also, below this table there is updated list of best hackers by summarized points, also the full list was updated [here](http://test.weaselcrow.com/pro/cf/hack2014/). [cut] <div></div> ### Accuracy rank | handle | accuracy | best rounds | points | :---:|:---:|:---:|:---:| 1 | [user:hetanglianyi,2014-12-25] | 100.0% | <small>[contest:462] [+19-0]</small> | 1900 (+19-0) | 2 | [user:bmerry,2014-12-25] | 100.0% | <small>[c...

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Hack me! — Year 2014 in review! (part 1.) Hey there! Since new year is coming, I want to start little summing-up of the ending one (of course we still talk about hacks :)). I wrote another short script, which purpose was to summarize all hacks in the 2014. I wanted to upload it after two last rounds, but mostly because of little differences (especially between first and second place), I did it before last rounds. Maybe the next rounds will be more exciting because of it. Below there is a list of 50 best hackers in this year <s>(so far)</s>, the full list can be found [here](http://test.weaselcrow.com/pro/cf/hack2014/). <strong>Update: </strong> After last round, the ranking was updated. The last round was decisive: [user:mosiomohsen,2014-12-31] made 5 successful hacks and 1 unsuccessful and with 450 points, he managed to surpass [user:anta,2014-12-31]. Congratulations! [cut] <div></div> rank | handle | points | best rounds | accuracy | :---:|:---:|:---:|:---:| 1 | [user:mosiomohsen,2014-12-31] | 8...

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Республиканская Олимпиада по информатике 2023 [2022](https://codeforces.me/blog/entry/102044) [2021](https://codeforces.me/blog/entry/90111) [2020](https://codeforces.me/blog/entry/80808) [2019](https://respa.daryn.kz/) [2018](https://codeforces.me/blog/entry/58432) [2017](https://codeforces.me/blog/entry/51416) **9 класс** | *Место* | *ФИО* | *CF handle* | *Балл* | *Медаль*| |----------|----------|----------| | 1 | Иса Ахмет | [user:Issa,2023-03-23] | 388 | | | 2 | Мамадахунов Мансур | [user:Wansur,2023-03-23] | 374 | | | 3 | Асланов Амир | [user:Aslanov,2023-03-23] | 330 | | | 4 | Серазитдинов Назар | [user:Otalp,2023-03-23]| 316 |...

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Need Help in optimizing my code from Div-2 D Problem round #388 Here is my code for this problem &mdash; http://codeforces.me/contest/749/problem/D from Div-2 D round #388 Here is my submission --> http://codeforces.me/contest/749/submission/23178341 My code is well commented and as per the editorial given. It is taking too much time. The complexity is O(nlog(n)). How do I optimize my code? What operation/operations are taking too long ? Please Help! Thanks in advance.

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Stuck in a problem The problem is [this](http://codeforces.me/contest/388/problem/A). The editorial says this:- We need some observation: There exists an optimal solution such that: in any pile, the box on the higher position will have a smaller strength. Let k be the minimal number of piles, then there exists an optimal solution such that: The height of all piles is n/k or n/k+1 (if n%k=0, then all of them have the height n/k). We can prove them by exchange argument: from an optimal solution, swap the boxes in it to make above property holds, and we can ensure it will remain valid while swapping. Then for a given k, we can check whether there exist a solution: the i-th (indexed from 0) smallest strength needs to be at least i/k. So we can do binary search (or just enumerate, since n is only 100) on k. Doubt: Why does the ith index need to be atleast i /k ?

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Hail Codechef So again Codechef has done another good thing now. Yes, now its setters copied a question of Long challenge from Codeforces. Yes, The Simple Game question(Question 1 od Div 1) is copied from https://codeforces.me/problemset/problem/388/C. This was the last thing to be seen. It can't handle contests properly. It can't handle ICPC correctly. It always makes contests unrated. So, why is this website running? Really becoming frustrated with day by day. Wherein codeforces, not a single question is wrong(exceptions, only occasionally), therein codechef, just a few contests are rated. Guys, can you give me a count of good-rated contests? Now I know, just people will downvote, like my other blog because, they are the ones, who just shout in codechef discuss that codechef is bad and all and shows here fake enthusiasm/love or codechef. Now if you want, go ahead, downvote, but if you agree to some of the points I said, express your views. P.S.- I am not a noob coder of 1 star/newbie. I am expe...

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Need help in a 1400 rated problem I am solving this problem and I am unable to solve it. I read the editorial but don't understand it. I feel sad to not even understand the editorial of a 1400 rated problem. https://codeforces.me/problemset/problem/388/A Can someone please explain this to me? Thanks.

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Первый рейтинг Прошло дня 3 с того момента как мне забанили предыдущий аккаунт, но я решил, что не буду сдавться и буду честно идти до оранжевых букв в нике (а может и черных), +388 к рейтингу не плохо, но всегда можно лучше. Дальше &mdash; больше

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Codeforces Round #388 (Div. 2) Editorial [tutorial:749A] [tutorial:749B] [tutorial:749C] [tutorial:749D] [tutorial:749E]

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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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Teams going to Gwalior/Pune Regionals **UPDATE:** I've uploaded the code that I used to generate this on Github, in case someone needs to generate something similar: [Codeforces Team Rating Calculator](https://github.com/abdullah768/Codeforces-Team-Rating-Calculator) The regional round has ended and here's the final Ranklist: https://www.codechef.com/public/rankings/ACM18GWR Inspired by the list of teams going to Kharagpur regionals, I decided to make one for Gwalior/Pune regionals. The list contains all the teams from the official Gwalior website. If you know the usernames of members of any of the teams. Please update the excel file: ### [HERE] (https://docs.google.com/spreadsheets/d/1jRvwzQzp1DOcazgI7jXBB8uY3u7Ze_eQ77Xa75_Q810/edit?usp=sharing) Team rating calculation has been done according to the official Codeforces team rating calculation formula. The table will be updated with details from the excel file every 6 hours or so. Last Updated: 10 pm, 12th December IST | No. | AIR | Team Name ...

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First Ever Users to Reach Some Rating Milestones Hi there! Recently after [contest:1696] [user:Um_nik,2022-06-29] [noticed](https://t.me/umnik_team_eng/2201) that he might be the ninth or tenth person to reach <b>3600</b> rating points, but still he did it earlier than [user:Petr,2022-06-29]. I wondered whether [user:Um_nik,2022-06-29] really was <i>that</i> attentive to know for sure how many people reached <b>3600</b> before him. As this is an objective truth or an objective misconception, I decided to simply check it. [cut] After several hours of programming and abusing Codeforces API I am ready to state that [user:Um_nik,2022-06-29] was indeed correct — he and [user:jiangly,2022-06-29] both broke through the <b>3600</b> mark simultaneously, being the ninth and tenth person to achieve it. I wanted to get more interesting facts from the fetched information — for example, although [user:Petr,2022-06-29]'s maximum is <b>3597</b> and he hasn't got to <b>3600</b> so far, he was the second one to get to <b>3550</b> points, and ...

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Milestones: ratings above 1500 and greatest falls (2024 edition) <i>Note.</i> This is an updated version of [this post](https://codeforces.me/blog/entry/104681). If you like [this style](https://codeforces.me/blog/entry/104320) more, please tell me in the comments. Since [user:tourist,2024-09-05]'s [breakthrough](https://codeforces.me/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 (by absolute value) negative rating changes. The second one is the first users ever to reach some rating value. [cut] First table: <spoiler> <table> <tr> <th>Place</th> <th>&Delta;</th> <th>Person</th> </tr> ...

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First Ever Users to Reach Some Rating Milestones Revised: ratings above 1500 and greatest falls Several days ago I published a [table](https://codeforces.me/blog/entry/104320) with first people to reach certain ratings. It was a bit raw because, firstly, it was based on top 20000 Codeforces users by rating, and, secondly, because it only gave information about ratings divisible by 50. Now I have prepared a table that is of more complex design, but both issues are resolved. Good luck understanding what is going on in it. [cut] For several reasons I firstly put another table. This is the table of greatest rating falls 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 fall in ratings if you are high-rated. 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 right, but if someone finds it, you're welcome to pu...

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