Codeforces: Domains For Groups Hello! Are you missing something new? I have something to please you. Regularly I host some events — Olympiads, onsites, and eventually, examinations and tests for students. On the one hand, Codeforces already offers a unique functionality — groups, the integration with Polygon, the possibility of choosing tasks from the archive and so on. But it doesn’t enough! ### Domains for groups Here is an example of such a group. It is open for all — join it and look: http://example.contest.codeforces.com ##### Domain Now when you are editing a group, you can specify its subdomain (from 3 to 20 alphanumeric characters, starts with a letter). When you specify the domain, the group will be accessible by a link http://yourgroupdomain.contest.codeforces.com. According to this link, the following is correct: * Nothing extra will be displayed — the site contains only the information about competitions and blogs of your group and nothing else. * A...

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Cormen Medal 2013 After a short delay (but Oscar is given in spring too, huh?) we are pleased to announce the Cormen Medal laureates for 2013. This year, we’ve decided to slightly upgrade nominations again, so this year's Cormen Medal is given in two nominations: * Best Progress * Best Problemsetter ## Best Progress <center> <img src="http://assets.codeforces.com/images/cormen-2013/scott_wu.jpg"> </center> The Cormen Medal laureate in this nomination is Scott Wu ([user:scott_wu,2014-05-12], USA). Note the [sharp upward dive his rating line takes](/profile/scott_wu). His achievements in 2013 are not limited by the spectacular dive into the best 10 participants on Codeforces: he got the 5-th place on IOI, won the 2013 season of the USACO contests, got target on TopCoder! We congratulate Scott and wish him many more achievements! ## Best Problemsetter <center> <img src="http://assets.codeforces.com/images/cormen-2013/Sereja-small.jpg"> </center> We didn't have to search far and ...

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Cormen Medal 2012 Hooray! Yupee! We have finished the complex me-Cormen-[user:ralekseenkov,2013-05-10] logistic combination and now are ready to pay tribute to the heroes of 2012. This year (thanks, Thomas!) the Cormen Medal laureates are going to get a new Thomas Cormen book "Algorithms Unlocked", signed by the author in addition to the medal, glory and fame! <img src="http://assets.codeforces.com/images/cormen-medal-2012-tourist-book.png" style="float:right;margin:1em 0 1em 1em;width:350px;"/> The 2012 Cormen Medal laureates are: - [user:tourist,2013-05-09] (Gennady Korotkevich) &mdash; Codeforces Best Coder 2012<br> Gennady keeps his first place in the Codeforces rating, continues participating actively and at this point the third place in the round isn’t always a rating improvement for him. We wish Gennady more victories, especially considering that the ACM-ICPC 2013 Finals are so soon! - [user:witua,2013-05-09] (Vitaliy Herasymiv) &mdash; Codeforces Best Problemse...

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700 contests. ruban's interview Please meet my today's guest Anatoly [user:ruban,2021-05-17], PhD in Physics and Mathematics, who yesterday participated in his 700th contest on Codeforces.  [cut] _._ _-Hello Anatoly_ -Hello Natalia _-Were you surprised by my message that you had taken more contests on Codeforces than anybody else?_ -No, I wasn’t. I knew it for sure. There have been only several occasions when I missed rounds because of high rating, I think, not many than 20-30. _-Do you feel something special about contests with the round number like 500th, 600th or this one 700th?_ -No, I wouldn't pay any attention if there were no interview. _-How did you start on Codeforces?_ -Since 2001 (long before Codeforces) I have coached the competitive programming team of [SibSUTIS](https://sibsutis.ru/en/) &mdash; Siberian State University of Telecommunications and Information Science and created problems for All...

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Cormen Medal 2011 <h4> On January, 27 we summed up the results and rewarded the laureates. They are: </h4> <center> <table> <tr> <td> <img src="http://assets.codeforces.com/images/cormen-2011/tourist.png" style="height:200px;"/> <br> <small>[[user:tourist]] <br/> The Best Codeforces Participant 2011</small> </td> <td> <img src="http://assets.codeforces.com/images/cormen-2011/Ripatti.png" style="height:200px;"/> <br> <small>[[user:Ripatti]] <br/> The Best Codeforces Problemsetter 2011</small> </td> <td> <img src="http://assets.codeforces.com/images/cormen-2011/Alex_KPR.png" style="height:200px;"/> <br> <small>[[user:Alex_KPR]] <br/> The Best Codeforces Blogger 2011</small> </td> </tr> </table> </center> <ul> <li> The Best Codeforces Participant 2011: Gennady [[user:tourist,2012-01-27]] Korotkyevich. We've recounted the rating taking only the 2011 rounds into consideration. Gennady topped the table well ahead of everybody else! You can follow <a href="http://codeforces.com/contes...

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Introduction to Disjoint Set Data Structure | DSU # Introduction to Disjoint Set Data Strucutres Hello Codeforces! I recently read about Disjoint Sets from the book Introduction to Algorithms and wanted to share the learnings in a simplified manner. So below article(and corresponding videos) is an attempt to create a good starting point for people who: 1. want to learn about DSU 2. practice some good DSU problems ## Contents 1. Introduction through an illustrative problem (video version: https://youtu.be/JDycPHW4kIs?si=WEp5Ft2jBWp9KnO2) 2. Sample SPOJ Problem and Implementation (video version: https://youtu.be/O4w-aX5mSks?si=vr0XSbyUswcXx-Yv) 3. Upcoming Practice Problems 4. Some Applications and References We will learn about disjoint set data structures and their operations union and find through a sample problem. ## Illustrative Problem Q: Given a undirected $Graph(V, E)$, answer Q queries of the form $(u, v)$ where answer to the query is True if there is a path from u to v, false otherwise. ![image](ht...

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Cormen Medal Laureates 2010 <img src="http://assets.codeforces.com/images/medals.gif" style="float:left;margin:0.5em 1em;width:150px;"> <p> The year 2010 is over and of course, we are all ready not only to meet the Old Style New Year, which is a Russian national holiday. We are also ready to learn the names of those awarded by the Cormen Medal in 2010. </p> <img src="http://assets.codeforces.com/images/tourist.jpg" style="float:right;margin:0.5em 1.75em;width:140px;"> <p> First, nomination "The Best 2010 Secondary School Contest Participant". And the winner is... (drum-roll) <a href="http://codeforces.com/profile/tourist">Gennady Korotkevich</a>. He took part in 5 out of 6 WPS (Winter Programming School) Olympiads organized by the Codeforces and won each of them! He participated individually in the team contest, but nevertheless got ahead of all the contestants.</p> <p> The Cormen Medal in &amp;quot;The Best 2010 Participant" nomination gets... <a href="http://codeforces.com/profile/tourist">Genna...

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Competitive Programming Resources Hi, I decided to post this blog to share various books and resources I used for Competitive Programming! I feel that these books were beneficial to my Competitive Programming journey. [user:lnishan,2022-11-26] posted [blog](https://codeforces.com/blog/entry/23054) that has a lot of extensive resources. [user:kostka,2022-11-25] has also posted a [blog](https://codeforces.com/blog/entry/109275#comments) with a really detailed book that is definitely worth checking out! [Codeforces Education](https://codeforces.com/edu/courses) is also a really great resource! **General Competitive Programming Books:** - [Competitive Programming Handbook](https://cses.fi/book.pdf) - [Competitive Programming 3](https://github.com/prasadgujar/CompetitiveProgramming/blob/master/book/Competitive%20Programming%203.pdf) - [The Hitchhiker's Guide to the Programming Contests](https://comscigate.com/Books/contests/icpc.pdf) "Introduction to Algorithms" by Cormen et. al. "Algorithms" by...

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Codeforces Round #377 Problem analysis (Unofficial) Since the official editorial is yet to be released and people are starting to ask for editorial, I decide to write this problem analysis and hopefully this may help the situation. =] Sorry for my bad English if I made some grammatical mistakes. [732A. Buying a shovel](http://codeforces.com/problemset/problem/732/A) --------------------- We could simulate the buying process &mdash; just buy until you can buy without change. As the problem statement have already stated, you can always buy 10 shovels without change, so there is at most 10 iterations. [C++ solution](http://codeforces.com/contest/732/submission/21587769) [732B. Cormen — The Best Friend Of a Man](http://codeforces.com/contest/732/problem/C) --------------------------------------- Iterate the days from left to right, and increase the days greedily on the right to fulfill the requirement. Take a look at this figure if you don't understand why this doesn't know why this works. ![ 732 example ](http...

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An awesome list for competitive programming! This is a project I started from late January 2016. My motive is that: Although there's fantastic information out there, I think they're still spread all over the place. Therefore, in my opinion it would probably be cool if there's an [awesome list](https://github.com/sindresorhus/awesome) for competitive programming! ( *It's now featured on the main list!* ) I'm actively updating the list here: [https://github.com/lnishan/awesome-competitive-programming](https://github.com/lnishan/awesome-competitive-programming) # Awesome Competitive Programming [](https://github.com/sindresorhus/awesome) A curated list of awesome `Competitive Programming`, `Algorithm` and `Data Structure` resources. Created with a view to connecting people to information, this list below contains a complete collection of all the fantastic resources I've collected over the course of my 11...

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Books... Hello, community ! I have scrolled some great blogs on [Codeforces](www.codeforces.com) and some websites(mentioned below) and found some resources. I hope that can help you, me and others. ## Books for Competitive Programming - [Competitive Programming](https://cpbook.net/), by Steven and Felix Halim. (The first edition is free for [download(pdf)](http://www.comp.nus.edu.sg/~stevenha/myteaching/competitive_programming/cp1.pdf)) - [Programming Challenges: The Programming Contest Training Manual](https://www.amazon.com/Programming-Challenges-Contest-Training-Computer/dp/0387001638), by Steven Skiena and Miguel Revilla - [Competitive Programmer's Handbook](https://cses.fi/book/index.html), by Antti Laaksonen. (Free to [download(pdf)](https://cses.fi/book/book.pdf)) - [Computational Geometry: Algorithms and Applications](https://www.amazon.com/Computational-Geometry-Applications-Mark-Berg/dp/3540779736), by Mark de Berg, Otfried Cheong, Marc van Kreveld, Mark Overmars...

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The Cormen Medal <img src="http://assets.codeforces.com/images/cormen-en.jpg" style="margin:0 1em;float:right;"> <p> Good day! </p> <p> We are pleased to inform you that on the night of December 31, 2010 on January 1, 2011 will be not only fireworks, champagne, gifts and presents, but we will summarize the <a href="http://codeforces.com/">Codeforces</a> year. Great news that <a href="http://en.wikipedia.org/wiki/Thomas_H._Cormen">Thomas Cormen</a> gave permission to use his name in Codeforces annual award. So, we are pleased to announce the annual Codeforces award — <b>the Cormen Medal</b>! </p> <p> It will be three awards this year: </p> <ul> <li>the best Codeforces participant</li> <li>the best secondary school Codeforces participant (based on <a href="http://codeforces.com/blog/entry/753">Winter Programming School Olympiads for Schoolchildred</a> results) </li> <li>the best problemsetter</li> </ul> <p> The first of the medals will be awarded to participant who will have the hi...

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Some thoughts about Surprise/Unknown Language Rounds I'm a huge fan of Surprise/Unknown Language Round competition format. Theoretically I enjoy participating in them, but in practice I mostly run them. What's so special about them that makes me like them so much? 1. They are unusual. At some point of time (which arrived pretty soon for me) traditional competitions pall and become a blur. If I give it a thought, I can clearly remember only a couple of the 80 SRMS and CF rounds I've done. The SRM which featured MooresLaw problem (great challenge phase and my only ever room win), TCO elimination round which I passed thanks to a last-minute submission on 500pt, a GCJ round from back when it was held on TopCoder platform, when I got stuck at input parsing and never got to the actual solution... and that's all. Marathon memory is a bit better, probably because I've participated in fewer of them, and each match took more time and effort. But unusual competitions leave the most lasting and vivid impression. 2. They fit my skills....

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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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Sorting Algorithm (C++ general implementation) In Algorithm Design, Sorting is an important part. Different algorithm use the sorting algorithm. Some Interesting sorting algorithm are include here: Bubble Sort, Heap Sort, Quick Sort, Counting Sort, Selection Sort, Insertion Sort etc.<br /><br />In computer science and mathematics, a sorting algorithm is an algorithm that puts elements of a list in a certain&nbsp; order. The most-used&nbsp; orders are numerical order and&nbsp; lexicographical order. Efficient&nbsp; sorting&nbsp; is important to optimizing the use of other algorithms (such as&nbsp; search&nbsp; and merge&nbsp; algorithms) that require sorted lists to work correctly; it is also often useful for&nbsp; canonicalizing&nbsp; data and for producing human-readable output.<br />Bubble Sort:<br /><br />Bubble sort is a simple sorting algorithm&nbsp; that works by repeatedly stepping through the list to be sorted, comparing each pair of adjacent items and&nbsp; swapping&nbsp; them if they are in the wrong order. The pass throu...

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Analysis on Plant problem (Code 185A) The first problem I will be discussing here, is "Plant", where a group of dwarves planted a very interesting recursive plant!! (Maybe the dream of any housewife? :p ) - **Solution's "entangled" recursive behaviour** More formally, we have a triangle, that on each new year is filled with one triangle on its inside, according to the following rules: - If the triangle is pointing up, it's filled with one triangle pointing down, now having 3 smaller triangles upwards and one triangle downwards. - If the triangle is pointing down, it is filled with one triangle pointing up, now having 3 smaller triangles downwards and one triangle upwards. These two rules will be the basis to build our solution. Let's denote as f(U, n) the number of upwards and downwards triangles that will be generated, if starting from year n with an upwards triangle and similarly f(D,n) the number of upwards and downwards triangles generated if we start on year n, with a downwards triangle. We now se...

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Latin American Regional Contests ICPC 2023 Teams Hello CF! **Next October 21st**, the regional contests in Latin America of the current ICPC cycle will be held simultaneously. These competitions will determine the teams that qualify for the Latin American Final. Although there is a list of the teams that will participate officially, I would love to know more about the competitors. What's your ICPC team in this edition? </br> <h1>All Teams with MaxRating</h1> <spoiler summary = "Open list"> <h1>All</h1> <table style="overflow: auto;"> <tr style="background-color: rgb(230, 224, 224);"> <th>Rank</th> <th>Name</th> <th>Country</th> <th>Member 1</th> <th>Member 2</th> <th>Member 3</th> <th>Rating</th> </tr> <tr style="background-color: rgb(255, 255, 255);"> <td>1</td> <td>teambrbr002</td> <td>Brazil</td> <td>[user:fmota,2023-10-16]</td> <td>[user:emaneru,2023-10-16]</td> <td>[user:MvKaio,2023-10-16]</td> <td>2662.6438</td> </t...

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Which maximum flow algorithm is this? I read Cormen and Wikipedia pages for Max flow algorithms, but I feel that I'm very confused right now. In my understanding, a max flow would basically work as follows: 1. Find an augmenting path and maintain a parent array. Should be O(E) using BFS. 2. Update the flow on all the edges on this path using the parent array. O(V) worst case. Update the max flow value. 3. Repeat the above steps until no more augmenting paths are found and return the max flow. My questions are: Ql. What is the limit on the number of times step 1 (bfs) is required? Q2. Is this Edmond Karp or Dinitz algorithm that I'm talking about? This is my first post, so I hope you will point out any problems in the way I've framed this question. Thanks.

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2024 Latin American Championship Teams On *October 21*, the regional competitions were held to determine the teams that will participate in **The 2024 ICPC Latin America Championship**. *404 teams* participated and *357 of them* solved at least one task. [Here](https://scorelatam.naquadah.com.br/latam-2023/) you can see the official standings. According to the qualification rules, **20 slots** should be allocated to the best-performing teams from all Latin America, with a general rule of at most **2 teams from the same institution**. The rest of the qualifiers will be chosen according to the algorithm established [here](https://drive.google.com/file/d/186s5Od43Dok_g5ILZYwPXEhstmmIlKoX/view). **UPD1: There will be a total of 42 spots!!** In addition to the initially considered 40 spots, the ICPC LATAM Steering Committee has approved 2 additional spots for the best all-female team in all of LATAM and for the best team from the host region **UPD2:** The [list](https://icpc.global/regionals/finder/Latin-America-Cha...

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Cormen Medal 2017 Hello Codeforces, Long awaited Cormen Medal is back this year! ## Nominations Without further ado here are the nomination for this year: - The most creative solution author - The most creative problem author ## Prizes The prizes for this year's winners are as follows: #### For the most creative solution - A beautiful trophy - The Art of Problem Solving, signed by Donald Knuth himself <img style="width: 500px;" src="https://c1.staticflickr.com/3/2211/2481198023_bbfc996d93_z.jpg?zz=1" /> #### For the most creative problem - A beautiful trophy - The Art of Problem Making, signed by Donald Trumpet himself <img style="width: 500px;" src="https://thisistopa.files.wordpress.com/2013/09/vermes.jpg" /> We are yet to decide the winners. So feel free to nominate your favorites so that we won't miss the best of the best. Who have been the most creative members of our community in 2016? Let your voice be heard in the comments.

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The 2024 ICPC Latin America Championship is near!! <div style="width: 100%; height: auto; max-width: 100%; overflow: hidden"> <img style="width: 100%; height: auto; display: block" src="https://acm.iteso.mx/share/pda2024.jpg" alt="" /> </div> <div style="text-align: center; margin-top: 10px"> <strong>Coordinated by ITESO University</strong> </div> <hr style="font-weight: 200" /> On **March 14**, the first ever ICPC Latin America Championship will begin, which will be called "Programmers of America" and will take place in Guadalajara. The regional contest represents the geographic area of Latin America. The contest is sponsored by Huawei, JetBrains, and Local Sponsors. The local website is available [here](http://pda2024.icpcmexico.org/). *42 teams* will participate, and the qualifiers for the World Final will be determined from them according to the [promotion rules](https://pda2024.icpcmexico.org/es/rules/). **Good luck to all teams!** <h1 style="margin-top: 30px">Qualified Teams</h1> ...

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How would you be a great competitive programmer from zero to hero How would you be a great competitive programmer from zero to hero ================== 1. Start by learning the basics of computer science and programming, such as data structures and algorithms. Recommended courses: "Introduction to Computer Science" and "Introduction to Programming" 2. Learn a programming language, such as C++ or Python. Recommended book: "The C++ Programming Language" by Bjarne Stroustrup or "Python Crash Course" by Eric Matthes 3. Learn how to implement basic data structures, such as arrays, linked lists, stacks, queues, and trees. Recommended book: "Introduction to Algorithms" by Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, and Clifford Stein 4. Learn how to implement basic algorithms, such as sorting, searching, and recursion. Recommended book: "Algorithms" by Robert Sedgewick and Kevin Wayne 5. Learn how to optimize your code for speed and memory usage. Recommended book: "Effective C++" by Scott Meyers 6. Learn more advanced algorithms and data...

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An awesome list for competitive programming! This is a project I started from late January 2016. My motive is that: Although there's fantastic information out there, I think they're still spread all over the place. Therefore, in my opinion it would probably be cool if there's an awesome list for competitive programming! ( It's now featured on the main list! ) I'm actively updating the list here: https://github.com/lnishan/awesome-competitive-programming Awesome Competitive Programming Awesome A curated list of awesome Competitive Programming, Algorithm and Data Structure resources. Created with a view to connecting people to information, this list below contains a complete collection of all the fantastic resources I've collected over the course of my 11-year competitive programming career. I hope you'll find it useful :) What is competitive programming? — Quora Contributing Please kindly follow CONTRIBUTING.md to get started. You can also contribute by sharing! Share the list with your classmates, your friends and eve...

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KMP for pattern searching.... hey guys i am finding it a bit difficult to understand KMP algo. I tried Cormen, Topcoder and many pdf's but still i am not able to grap the logic behind its working. Can anyone help :)

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