Competitive programming

Open championship on programming Yandex.Algorithm, August 22, 2013.

Competitive programming is a mind sport usually held over the Internet or a local network, involving participants trying to program according to provided specifications. Competitive programming is recognized and supported by several multinational software and Internet companies, such as Google,[1][2] Facebook[3] and IBM.[4] There are several organizations who host programming competitions on a regular basis.

A programming competition generally involves the host presenting a set of logical or mathematical problems to the contestants (who can vary in number from tens to several thousands), and contestants are required to write computer programs capable of solving each problem. Judging is based mostly upon number of problems solved and time spent for writing successful solutions, but may also include other factors (quality of output produced, execution time, program size etc.)

History

One of the oldest contests known is ACM ICPC which originated in the 1970s, and has grown to include 88 countries in its 2011 edition. Interest in competitive programming has grown extensively since 2000, and is strongly connected to the growth of the Internet, which facilitates holding international contests online, eliminating geographical problems.

Overview

The aim of competitive programming is to write source code of computer programs which are able to solve given problems. A vast majority of problems appearing in programming contests are mathematical or logical in nature. Typical such tasks belong to one of the following categories: combinatorics, number theory, graph theory, geometry, string analysis and data structures. Problems related to artificial intelligence are also popular in certain competitions.

Irrespective of the problem category, the process of solving a problem can be divided into two broad steps, constructing an efficient algorithm, and implementing the algorithm in a suitable programming language (the set of programming languages allowed varies from contest to contest). These are the two most commonly tested skills in programming competitions.

In most contests, the judging is done automatically by host machines, commonly known as judges. Every solution submitted by a contestant is run on the judge against a set of (usually secret) test cases. Normally, contest problems have an all-or-none marking system, meaning that a solution is "Accepted" only if it produces satisfactory results on all test cases run by the judge, and rejected otherwise. However, some contest problems may allow for partial scoring, depending on the number of test cases passed, the quality of the results, or some other specified criteria. Some other contests only require that the contestant submit the output corresponding to given input data, in which case the judge only has to analyze the submitted output data.

Notable competitions

There are two types of competition formats: short-term and long-term. Each round of short-term competition lasts from 1 to 3 hours. Long-term competitions can last from a few days to a few months.

Short-term


In most of the above competitions, since the number of contestants are quite large, competitions are usually organized in several rounds. They usually require online participation in all rounds except the last, which require onsite participation. A special exception to this is IEEEXtreme, which is a yearly 24-hour virtual programming competition. The top performers at IOI and ACM ICPC receive gold, silver and bronze medals while in the other contests, cash prizes are awarded to the top finishers. Also hitting the top places in the score tables of such competitions may attract interest of recruiters from software and Internet companies.

Long-term

Online contest and training resources

The programming community around the world has created and maintained several internet-resources dedicated to competitive programming. They offer standalone contests with or without minor prizes. Also the past archives of problems are a popular resource for training in competitive programming. These include:

Name Description Website
TopCoder US resource and company, which organizes contests and also provides industrial problems as a kind of free-lance job; it offers dozens of short contests and several long ("marathons") every year. Specific feature - participants have a chance to check correctness of other contestants' solutions after coding phase and before final automatic testing (so called "challenge phase"). www.topcoder.com
SPOJ Polish online judge system which provides a lot of problems for training, and provides a platform for other organizers to host their programming contests. www.spoj.com
Codeforces Russian resource, maintained by Saratov State University, which mostly provides frequent (up to two per week) short contests. Special features: ability to check correctness of other contestants' solutions during "coding phase", virtual contests, trainings etc. codeforces.com
Internet Problem Solving Contest Annual contest for teams up to three people. ipsc.ksp.sk
UVa Online Judge Contains over 3,500 problems for practicing. Hosts regular online competitions. uva.onlinejudge.org
CodeChef Maintained by Directi, it hosts a 10-day-long contest and a couple of short contests every month (one IOI styled and other ACM ICPC styled), and provides a contest hosting platform to educational institutions for free. The top two winners of the long contest win cash prizes while the top 10 global get a tee-shirt. www.codechef.com
CodeAbbey collection of over 160 beginner-level problems and exercises for practicing programming (awarding "certificates" for solving 125 of them) www.codeabbey.com
LightOJ Light Online Judge - a Bangladeshi web-site containing hundreds of categorized problems for practice. Users can also host their own contests by uploading dataset or selecting problems from LightOJ. lightoj.com
Timus Online Judge Russian website with more than a thousand problems in Russian and English, maintained by Ural State University, which mostly provides ~10 contests per year.
Peking University Online Judge Chinese web-site with about 3000 programming puzzles in English.
Caribbean Online Judge Spanish resource, maintained by University of Information Science. Contains over 3,000 problems for practicing. Also hosts regular online competitions.
HackerEarth Bangalore, India based company providing online contest like environment aiming at providing recruitment assessment solutions.
HackerRank "Most Innovative" Competitive Programming website. It was started in 2012, and offers programming problems in different domains of Computer Science. It also hosts annual Codesprints which help connect the coders and Silicon Valley startups.
CodinGame CodinGame is an online gaming platform that provides solo and multiplayer games for programmers and also hosts monthly international online coding contests.
Competitive Programming Network organization that promotes trainings in competitive programming through periodic programming contests.
Project Euler Large collection of computational math problems (i.e. not directly related to programming but often requiring programming skills for solving).
Coderbyte Website that provides programming challenges that you can solve in several languages in an online editor (70+ exercises and 3 contests as of August 2014).
CheckiO A website which provides Python based programming challenges in a game-like environment.

References

External links

Open-source project for running contests: