A curated list of awesome competitive programming / algorithm / data structure resources.
This list was created with a view to connect more people to information. It's aimed to cover a wide range of aspects and be a useful list for all.
What is competitive programming? - Quora
Please kindly follow CONTRIBUTING.md to get started (including TODOs).
Awesome websites to lookup and learn algorithms and data structures.
| ☆ | Name | Description |
|---|---|---|
| ★★★ | topcoder Data Science Tutorials | This is a list of tutorials written by respected topcoder members. Many top programmers started learning data sciences from here. |
| ★★★ | E-Maxx (Russian), (English) | Emaxx is widely used in the Russian-speaking competitive programming community. Only a small fraction of the original site is translated into English, but Google Translate would work okay. |
| ★★☆ | Algorithms - GeeksforGeeks | Geeksforgeeks has a large amount of nicely written articles on different topics. It is a great complimentary resource for algorithm courses. |
| ★★☆ | PEGWiki | PEGWiki has amazing in-depth wiki-like writeups on many topics. It's far better than those on Wikipedia in my opinion. |
| ★★☆ | Notes - HackerEarth | A great crowdsourcing platform for tutorials. Also visit Code Monk. |
| ★★☆ | USA Computing Olympiad (USACO) | USACO contains several training pages on its website which are designed to develop one's skills in programming solutions to difficult and varied algorithmic problems at one's own pace. |
| ★☆☆ | OLYMPIADS IN INFORMATICS | An international journal focused on the research and practice of professionals who are working in the field of teaching and learning informatics to talented student. |
| ★☆☆ | algolist (Russian) | algolist is a website devoted to algorithms of all sorts. |
| ★★☆ | 演算法筆記 (Algorithm Notes) (Chinese) | 演算法筆記 is one of the most popular tutorial websites among the Taiwanese competitive programming community. The maintainer for this website spends immense efforts on researching algorithms. |
| ★★☆ | 国家集训队论文 1999-2015 (Papers from Chinese IOI training camps) (Chinese) | These are papers from the Chinese IOI training camps. It's interesting for the fact that one can tell different regions emphasize different things. |
Find out what topics you need to learn.
| ☆ | Name | Description |
|---|---|---|
| ★★★ | IOI Syllabus | A detailed syllabus on which IOI contestants will be tested. This is still somewhat relevant to ACM-ICPC. |
| ★★☆ | Programming Camp Syllabus | A list of important topics in competitive programming with exercise problems. |
These are some other awesome curated lists.
| ☆ | Name | Description |
|---|---|---|
| ★★★ | Good Blog Post Resources about Algorithm and Data Structures - Codeforces | A collection of fantastic tutorial blog posts written by Codeforces users. Some intriguing ones include Palindromic Trees, Policy Based Data Structures, and a lot more. |
| ★★★ | Data Structures and Algorithms - CodeChef Discuss | A very complete list of competitive programming resources. A must-have in your browser bookmark. |
| ★☆☆ | hkirat/Algorithmic-Resources | This list collected materials for some relevant topics in competitive programming. |
Algorithm / Data structure implementations.
It is advised that you write your own ones before looking at others'.
| ☆ | Name | Description |
|---|---|---|
| ★★★ | CodeLibrary, by Andrey Naumenko (indy256) | This site contains a large collection of implementations for algorithms and data structures in Java and C++. You may also visit his GitHub Repository. |
| ★★☆ | Stanford University ACM Team Notebook (2014-15) | Stanford's team notebook is well maintained and the codes within are high-quality. |
| ★★☆ | bobogei81123/bcw_codebook, by team bcw0x1bd2 (darkhh, bobogei81123, step5) from National Taiwan University | bcw0x1bd2 is the team representing National Taiwan University for the 2016 ACM-ICPC World Finals. This notebook contains robust implementations for advanced data structures and algorithms. |
| ★☆☆ | SuprDewd/CompetitiveProgramming, by team viRUs from Reykjavik University | One of the very few notebooks to include a tester (even integration with Travis CI). A great notebook to learn from. |
| ★☆☆ | foreverbell/acm-icpc-cheat-sheet, by foreverbell (foreverbell) | A notebook with some advanced data structures and algorithms including some from the China informatics scene. |
| ★★☆ | Spaghetti Source - 各種アルゴリズムの C++ による実装 (Japanese), by 前原 貴憲 (maehara) | A neatly categorized notebook in Japanese. This website is no longer being updated, but the topics discussed here are still relevant. |
| ★☆☆ | igor's code archive, by Igor Naverniouk (Abednego) | A good notebook by Igor Naverniouk who is currently a software engineer at Google and part of the Google Code Jam team. |
| ★★☆ | PetarV-/Algorithms, by Petar Veličković (PetarV) | An occasionally updated assorted list of data structures and algorithms' implementations in C++, which at times extends beyond what is necessary for competitive programming. Most of the implementations have been "battle-tested" in previous contests. |
This section mainly focuses on languages and other miscellaneous knowledge.
| ☆ | Name | Description |
|---|---|---|
| ★★☆ | Power up C++ with the Standard Template Library - topcoder: Part 1, Part 2 | Learn how to use basic C++ standard template libraries. |
| ★★☆ | Yet again on C++ input/output - Codeforces | Learn more about C++ I/O optimizations. |
| ★★☆ | C++ Tricks - Codeforces ... What are some cool C++ tricks to use in a programming contest? - Quora | Plentiful C++ tricks for competitive programming. Note that some should be used with care. |
| ★★★ | C++ STL: Policy based data structures - Codeforces: Part 1, Part 2 | Detailed introduction to the extra data structures implemented in GNU C++. The official documentation can be found here. |
| ★☆☆ | C++11 FAQ (English, Chinese, Russian, Japanese, Korean) | A list of FAQs regarding C++11 collected and written by Bjarne Stroustrup, the creator of C++. |
| ☆ | Name | Description |
|---|---|---|
| ★★☆ | How to read input in Java — tutorial - Codeforces | Learn how to read input faster |
| ★★☆ | How to sort arrays in Java and avoid TLE - Codeforces | Some tips on how to avoid hitting the worst case of quick sort |
| ★★☆ | Java.math.BigInteger Class - TutorialPrint | A quick reference for the famous BigInteger class in Java |
| ★★☆ | BigNum arithmetic in Java — Let's outperform BigInteger! - Codeforces | A basic but faster custom BigInteger class |
| ★★☆ | EZ Collections, EZ Life (new Java library for contests) - Codeforces | A Java library for contests written by Alexey Dergunov (dalex) |
| ☆ | Name | Description |
|---|---|---|
| ★★★ | Bit Twiddling Hacks | A huge compiled list of bit manipulation tricks. |
| ★★★ | Comparing Floating Point Numbers, 2012 Edition - Random ASCII | This post teaches everything one needs to know about floating point numbers. A must read especially for geometry topics. |
| ★★☆ | 你应该知道的浮点数基础知识 • cenalulu's Tech Blog (Chinese) | A similar post on floating point numbers. |
| ★★☆ | Object-Oriented C Style Languages: C++, Objective-C, Java, C# - a side-by-side reference sheet | A detailed side-by-side reference sheet for common syntaxes. |
Awesome tools that will make your life easier.
| ☆ | Name | Description |
|---|---|---|
| ★★★ | VisuAlgo | VisuAlgo features a large collection of visualization tools for algorithms and data structures. |
| ★★★ | General Practice Helpers: ... ☘CHelper☘ (IntelliJ IDEA) (manual) ... ☘caide☘ (Visual Studio, CodeLite) ... ☘JHelper☘ (AppCode, CLion) | These tools parse contests, inline library codes and provide testing frameworks. |
| ★★☆ | Codeforces Parsers: ... ☘Codeforces Parser☘ ... ☘GoCF☘ ... ☘cfparser☘ (emacs) | These tools parse Codeforces contest problems and help run sample tests. |
| ★★★ | The On-Line Encyclopedia of Integer Sequences (OEIS) | A stunning encyclopedia with a database of countless integer sequences. It also features a powerful search engine. Sometimes a seemingly difficult combinatorics problem can be equivalent to a simple or known and studied integer sequence. |
| ★★☆ | Ineffable | Ineffable is a simple command-line grader for local grading. |
| ☆ | Name | Description |
|---|---|---|
| ★★★ | polygon | polygon provides a platform and a rich set of tools for professional contest preparation. ... An example: Validators with testlib.h - Codeforces |
| ★☆☆ | A simple tool for graph visualization | This is a very simple tool to visualize small graphs. |
| ★★★ | Virtual Judge (vjudge) | Virtual Judge (vjudge) allows users to create virtual contests with problems from notable problem archives. |
| ★★☆ | BNU Online Judge | BNU Online Judge also allows users to create virtual contests. |
| ★★☆ | Kattis | Kattis assists in contest preparation (E-mail them for assistance). |
It's highly recommended that you begin your competitive programming journey with these awesome courses!
| ☆ | Name | Description |
|---|---|---|
| ★★☆ | Code Monk, by HackerEarth | This is a fantastic step-by-step guide to gear you up with some essential topics in competitive programming. |
| ★★★ | Stanford CS 97SI: Introduction to Competitive Programming Contests | This course offers comprehensive lecture slides and a short list of exercise problems. |
| ★★☆ | Reykjavik T-414-ÁFLV: A Competitive Programming Course | An awesome course taught by Bjarki Ágúst Guðmundsson (SuprDewd). These lectures feature neat slides and a nice list of problems to practice. |
| ★★☆ | NCTU DCP4631: Problem Solving and Programming Techniques | A course on basic topics featuring good lecture slides. |
| ★☆☆ | 建國中學資訊科培訓 (CKHS Training) (Chinese) | Good lecture materials made by CKHS Infor Club. |
| ☆ | Name | Description |
|---|---|---|
| ★★★ | prakhar1989/awesome-courses#algorithms | A fantastic list of open courses offered by notable institutions (MIT, Stanford, UC Berkeley ... etc.). |
| ★★★ | MIT SMA 5503: Introduction to Algorithms | This one isn't included on the list above, but it's by far my personal favorite. This course was lectured by Prof. Charles Leiserson (coauthor of Introduction to Algorithms) and Prof. Erik Demaine who is a brilliant and established scholar in the field. The course offered great materials and generally more intuitive proofs and analyses. |
A list of recommended books for competitive programming.
| ☆ | Name | Description |
|---|---|---|
| ★★☆ | Competitive Programming, by Steven and Felix Halim | This book contains a collection of relevant data structures, algorithms, and programming tips. It's a well-received book. ... The first edition is free for download (pdf). |
| ★★☆ | Programming Challenges: The Programming Contest Training Manual, by Steven Skiena and Miguel Revilla | This book includes more than 100 programming challenges, as well as the theory and key concepts necessary for approaching them. Problems are organized by topic, and supplemented by complete tutorial material. |
| ★★★ | Looking for a Challenge, written by a group of authors associated with the Polish Olympiads | Most of the problems described in the book are really hard but they are explained in such a way that even beginners can understand. It appears to be out of stock (as of May, 2016), but you can reserve one on their official website. |
| ★★☆ | Computational Geometry: Algorithms and Applications, by Mark de Berg, Otfried Cheong, Marc van Kreveld, Mark Overmars | This is a well-written book which covers a broad range of computational geometry problems. |
| ★☆☆ | The Hitchhiker’s Guide to the Programming Contests, by Nite Nimajneb | This book is free for download (pdf). This book covered various topics relevant to competitive programming. |
| ★★★ | プログラミングコンテストチャレンジブック (Japanese), by 秋葉拓哉, 岩田陽一, 北川宜稔 | 培養與鍛鍊程式設計的邏輯腦：世界級程式設計大賽的知識、心得與解題分享 (Chinese Traditional) |
| ★★☆ | 算法竞赛入门经典 (Chinese), by 刘汝佳 | The Art of Algorithms and Programming Contests (English), 打下好基礎：程式設計與演算法競賽入門經典 (Chinese Traditional) |
| ★★☆ | 算法竞赛入门经典——训练指南 (Chinese), by 刘汝佳, 陈锋 | 提升程式設計的解題思考力─國際演算法程式設計競賽訓練指南 (Chinese Traditional) |
| ★★★ | 算法艺术与信息学竞赛 (Chinese), by 刘汝佳, 黄亮 |
| ☆ | Name | Description |
|---|---|---|
| ★★★ | Introduction to Algorithms, by Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest and Clifford Stein | Also known as CLRS (taken from name initials), this book is often referred to as the "bible" for algorithms and data structures. It's one of the most popular textbooks for university algorithm courses. This book covered various algorithms and data structures in great detail. The writing is more rigorous and can be difficult to some. |
| ★★☆ | Algorithm Design, by Jon Kleinberg and Éva Tardos | This book revolves around techniques for designing algorithms. It's well-organized and written in a clear, understandable language. Each chapter is backed with practical examples and helpful exercises. The chapter on network flow is highly praised by lots. ... The lecture slides that accompany the textbook are available on its official website. |
| ★★☆ | The Algorithm Design Manual, by Steven S. Skiena | The book is written in more readable text. Some find it comprehensive than other books. You can also find some good resources (including the author's own video lectures) on its official website. |
| ★★★ | Algorithms, by Robert Sedgewick and Kevin Wayne | This book is neatly categorized, coupled with elaborate explanations and fantastic illustrations. It is used in some IOI training camps as a textbook. |
| ☆ | Name | Description |
|---|---|---|
| ★★☆ | Discrete Mathematics and Its Applications, by Kenneth H. Rosen | Discrete Mathematics is closely relevant to competitive programming. This book provides comprehensive materials on a wide range of topics including: Logics and Proofs, Sets, Functions, Sequences, Matrices, Number Theory, Recursion, Counting, Probablity, Graphs, Trees and Boolean Alegra to name but a few. |
| ★★☆ | Concrete Mathematics: A Foundation for Computer Science, by Ronald L. Graham, Donald E. Knuth, Oren Patashnik | The book offers a deeper insight into Discrete Mathematics with more emphases on number-related topics. |
| ★★☆ | Linear Algebra and Its Applications, by David C. Lay, Steven R. Lay, Judi J. McDonald | The book does a brilliant job at bridging the gap between a physical system (for scientists and engineers) and an abstract system (for mathematicians). |
| ★★☆ | Introduction to Probability, by Charles M. Grinstead, J. Laurie Snell | This is a well-written introductory probabilities book. ... It's free for download (pdf) (released under GNU Free Documentation License). |
| ★★☆ | How to Solve It: A New Aspect of Mathematical Method, by G. Polya | An old-time classic. In this book, the author provides a systematic way to solve problems creatively. |
Good online judges / contest platforms to practice.
| ☆ | Name | Description |
|---|---|---|
| ★★★ | Codeforces | Codeforces is one of, if not, the most popular contest platforms out there. Currently maintained by Saratov State University, it features regular contests and countless awesome original problems. Additionally, every contest provides immediate helpful tutorials (usually) written by the authors themselves. Codeforces also houses a strong and engaging community. All in all, one would indeed learn and improve tremendously here. |
| ★★★ | topcoder | topcoder has been around since 2001. Rich in history, It's considered to be one of the most prestigious organizations when it comes to technology competitions. Hundreds of SRMs gave birth to an abundant problemset. Problems here are typically more challenging than others and topcoder therefore appeals to many elite programmers. The annual topcoder Open (TCO) is also a widely-discussed event. |
| ★★★ | Google Code Jam | Google Code Jam is certainly one of the most highly-esteemed programming competitions. The competition consists of unique programming challenges which must be solved in a fixed amount of time. Competitors may use any programming language and development environment to obtain their solutions. |
| ★★☆ | CodeChef | CodeChef is a non-profit educational initiative of Directi. It's a global competitive programming platform and has a large community of programmers that helps students and professionals test and improve their coding skills. Its objective is to provide a platform for practice, competition and improvement for both students and professional software developers. Apart from this, it aims to reach out to students while they are young and inculcate a culture of programming in India. |
| ★★★ | SPOJ | The SPOJ platform is centered around an online judge system. It holds a staggering amount of problems prepared by its community of problem setters or taken from previous programming contests, some of which are great problems for practice (refer to the Problem classifiers section). SPOJ also allows advanced users to organize contests under their own rules. |
| ★★☆ | Timus | Timus Online Judge is the largest Russian archive of programming problems with automatic judging system. Problems are mostly collected from contests held at the Ural Federal University, Ural Championships, Ural ACM ICPC Subregional Contests, and Petrozavodsk Training Camps. |
| ★★☆ | SGU | SGU is an old-school online judge maintained by Saratov State University. A renowned competitive programmer - Huang I-Wen (dreamoon) thinks that it's the hardest online judge because its problems require unusual skills. |
| ★☆☆ | HDU | HDU is an online judge maintained by Hangzhou Dianzi University. It's home to many classic problems from the Chinese IOI scene. |
| ★★☆ | UVa | An old-school problem archive / online judge with rich history. Thousands of problems, including many classic ones, are featured here. However, it is strongly advised that you practice with uHunt following its "Competitive Programming Exercise" section. |
| ★★☆ | HackerRank | HackerRank is a company that focuses on competitive programming challenges for both consumers and businesses. HackerRank's programming challenges can be solved in a variety of programming languages and span multiple computer science domains. |
| ★★★ | POJ | POJ is an online judge with many great problems maintained by Peking University. Most Chinese competitive programmers began their journey here. |
| ★★☆ | Project Euler | Project Euler features a stunning set of good math problems. It also hosts a forum where people can discuss. |
| ★☆☆ | Hackerearth | HackerEarth is a startup technology company based in Bangalore, India that provides recruitment solutions. |
| ★★☆ | Aizu Online Judge | Aizu online judge is a contest platform and problem archive hosted by The University of Aizu. It has a lot of great problems from programming competitions in Japan. |
Sites classifying programming problems.
You can choose a category (eg. DP) of interest and practice problems on that topic.
| ☆ | Name | Description |
|---|---|---|
| ★★★ | A2 Online Judge | Mixed |
| ★★★ | Problem Classifier | SPOJ |
| ★★☆ | UVa Online Judge | CP Book |
| ★☆☆ | Codeforces Tags | CF (DP) |
| ★★☆ | HackerRank | HackerRank |
| ★★☆ | Lucky貓的 UVA（ACM）園地 (Chinese) | UVa |
Calendars for impending programming contests.
(Never miss another contest!)
| ☆ | Name | Description |
|---|---|---|
| ★★★ | Programming Contest Calendar - HackerRank | |
| ★★☆ | clist.by | |
| ★★☆ | Coding Calendar (Android App) | |
| ★★☆ | Coder's Calendar: Android App, Chrome Extension, Firefox Add-on | |
| ★★★ | CodeHorizon: iOS App, Android App |
These are great sites to ask questions.
Paste your codes at ideone, pastebin or other sites to avoid formatting issues.
| ☆ | Name | Description |
|---|---|---|
| ★★★ | Codeforces | For quick answers, Codeforces is definitely the go-to place to ask about anything competition-related. |
| ★★★ | Competitive Programming - Quora | You would typically get more elaborate answers on Quora, but you might not have your questions answered straightaway. |
| ★★☆ | Theoretical Computer Science Stack Exchange | This place is generally for the academics, so don't ask questions about contest problems here. |
Meet the god-like competitive programmers!
Learn helpful tips, tutorials and insights from these people :)
| Name (Handle) | Blog Name |
|---|---|
| Codeforces blogs | |
| Petr Mitrichev (Petr) | Algorithms Weekly |
| Bruce Merry (bmerry) | Entropy always increases |
| Przemysław Dębiak (Psyho) | Psyho's blog |
| Anudeep Nekkanti (anudeep2011) | Namespace Anudeep ;) |
| vexorian (vexorian) | vexorian's blog |
| Ashar Fuadi (fushar) | Fushar's blog |
| LiJie Chen (WJMZBMR) | WJMZBMR (Chinese) |
| Huang I-Wen (dreamoon) | 小月的耍廢日誌 (Chinese) |
| Po-Jui Chen (a00012025) | code倉庫 (Chinese) |
| Shiang-Yun Yang (morris1028) | Morris' Blog (Chinese) |
| Yuhao Du (TooDifficuIt, TooSimple, xudyh) | xudyh (Chinese, Emptied) |
| Dreadnought (TankEngineer, rowdark, AngryBacon) | Dreadnought's Wiki (Chinese) |
| Name (Handle) | Link |
|---|---|
| HackerRank Live Youtube | |
| Petr Mitrichev (Petr) | Youtube |
| Egor Kulikov (Egor) | Youtube |
| Adam Bardashevich (subscriber) | Youtube |
| Bohdan Pryshchenko (I_love_Tanya_Romanova) | Twitch, Youtube |
| Vladimir Smykalov (enot.1.10) | Twitch, Youtube |
| Aleksandar Abas (Alex7) | Youtube |
Visit Competitive Programming - Quora (Top 10 Most Viewed Writers).
Informative and helpful articles
| Subject |
|---|
| Overview of Programming Contests, by Przemysław Dębiak (Psyho) |
| The 'science' of training in competitive programming - Codeforces, by Thanh Trung Nguyen (I_love_Hoang_Yen) |
| If you ask me how to improve your algorithm competition skill, I will give you the link of this blog. - Codeforces, by Huang I-Wen (dreamoon) |
Fine answers to frequently-asked questions
Relevant awesome lists
| Repository |
|---|
| tayllan/awesome-algorithms |
| enjalot/algovis |
| rossant/awesome-math |
| fffaraz/awesome-cpp |
| akullpp/awesome-java |
| prakhar1989/awesome-courses |
| vhf/free-programming-books |
| Name | Description |
|---|---|
| LeetCode Video Tutorials | A set of videos explaining LeetCode problems. |
| 数据结构与算法/leetcode/lintcode题解 (LeetCode tutorials) (Chinese) | Tutorials on popular interview topics. |
Awesome Competitive Programming is licensed under a Creative Commons Attribution 4.0 International License.