Competitive programming


Competitive programming is a mind sport usually held over the Internet or a local network, involving participants trying to program according to provided specifications. Contestants are referred to as sport programmers. Competitive programming is recognized and supported by several multinational software and Internet companies, such as Google and Facebook. 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, also known as puzzles, to the contestants, 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

History

One of the oldest contests known is ICPC which originated in the 1970s, and has grown to include 88 countries in its 2011 edition.
From 1990 to 1994, Owen Astrachan, Vivek Khera and David Kotz ran one of the first distributed, internet-based programming contests inspired by ICPC.
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. 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 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.
Online judges are online environments in which testing takes place. Online judges have ranklists showing users with the biggest number of accepted solutions and/or shortest execution time for a particular problem.

Notable competitions

There are two types of competition formats: short-term and long-term. Each round of short-term competition lasts from 1 to 5 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 is quite large, competitions are usually organized in several rounds. They usually require online participation in all rounds except the last, which requires 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

Contest NameMain SponsorDescriptionRunning SinceUsual TimeNext Application CycleStatus
Multi-Agent Programming ContestClausthal University of Technology in conjunction with agent-oriented workshopsAnnual international programming competition to stimulate research in the area of multi-agent system development and programming.2005SeptSept 2011Active
Google Summer of CodeGoogle Inc.An annual program in which Google awards stipends to hundreds of students who successfully complete a requested free software / open-source coding project during the summer.2005Mar-AugMar 23- Apr 3Active
Google Highly Open Participation ContestGoogle Inc.A contest run by Google in 2007-8 aimed at high school students. The contest is designed to encourage high school students to participate in open source projects.2007Nov-FebUnknownUnknown

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:
NameDescriptionWebsite
CodeChefMaintained by Directi, it hosts a 10-day-long contest and a couple of short contests every month, 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.
CodeCupAnnual international board game AI programming competition organized by the Dutch Olympiad in Informatics since 2003.
CodeforcesRussian resource, maintained by ITMO University, which mostly provides frequent short contests. Special features: ability to check correctness of other contestants' solutions during "hacking phase", virtual contests, trainings etc.
CodinGamePuzzles, code golf. Hosts regular online competitions.
HackerEarthBangalore, India based company providing online contest like environment aiming at providing recruitment assessment solutions.
HackerRankHackerRank offers programming problems in different domains of Computer Science. It also hosts annual Codesprints which help connect the coders and Silicon Valley startups.
Project EulerLarge collection of computational math problems.
TopcoderUS 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 every year. Specific feature - participants have a chance to check correctness of other contestants' solutions after coding phase and before final automatic testing.
UVa Online JudgeContains over 4,500 problems for practising. Hosts regular online competitions. Opened in 1995, it is one of the oldest such websites.
SPOJPolish online judge system which provides a lot of problems for training, and provides a platform for other organizers to host their programming contests.
Open KattisPublic version of the Kattis contest management system, with an archive of over 2600 problems. Kattis was developed to aid computer science courses, but it's also used to host prestigious competitions, like ICPC World Finals.
AtCoderBased in Japan, Atcode offers online programming contests on a weekly basis. The contests are offered in the Japanese and English language.
Caribbean Online JudgeSpanish resource, maintained by University of Information Science. Contains over 3,000 problems for practicing. Also hosts regular online competitions.
Microprediction.OrgTurnkey prediction of live data accomplished through streaming contests.

Benefits and criticism

Participation in programming contests may increase student enthusiasm for computer science studies. The skills acquired in ICPC-like programming contests also improve career prospects, as they help to pass the "technical interviews", which often require candidates to solve complex programming and algorithmic problems on the spot.
There has also been criticism of competitive programming, particularly from professional software developers. One critical point is that many fast-paced programming contests teach competitors bad programming habits and code style. Also, by offering only small algorithmic puzzles with relatively short solutions, programming contests like ICPC and IOI don't necessarily teach good software engineering skills and practices, as real software projects typically have many thousands of lines of code and are developed by large teams over long periods of time. Peter Norvig stated that based on the available data, being a winner of programming contests correlated negatively with a programmer's performance at his or her job at Google.
Yet another sentiment is that rather than "wasting" their time on excessive competing by solving problems with known solutions, high-profile programmers should rather invest their time in solving real-world problems.

Literature