ACM International Collegiate Programming Contest
The ACM International Collegiate Programming Contest (ACM-ICPC) is a set of programming competitions sponsored by the Association for Computing Machinery (ACM). It consists of the World Finals and various Regional Contests used to select teams to advance to the World Finals.
The ACM contests are team competitions. Teams may consist of up to three contestants, all from the same post-secondary institution. They are similar in style to the individual informatics olympiads, with a few exceptions.
An ACM contest takes place on a single day, within the span of around five hours. The number of problems is variable, but is usually approximately 10. Solutions may be submitted in C, C++, and Java. A solution must be a single source file which uses only built-in libraries.
The problems are algorithmic in style, and are difficult because they must be solved by efficient algorithms. No points are awarded for code style or user interface design. Competitors' solutions, once submitted, are compiled and run against secret test data. A solution receives points if and only if it produces the correct output for given input within time and memory limits. Unlike in OIs, the time and memory limits are often not stated in ACM contests.
There is no partial scoring: a solution must pass all test cases for a given problem in order to receive credit for solving that problem. Teams are ranked by total number of problem solved. In case of a tie, teams are ranked by penalty points. For each problem solved, a team receives a number of penalty points equal to the number of minutes that elapsed between the start of the competition and the time when the team first submitted a correct solution. The team also receives 20 penalty minutes for every incorrect submission prior to the first correct submission. A team does not incur penalty points for a problem they do not ultimately solve.
Teams receive instant feedback on their own submissions. A live scoreboard showing all teams is available to the participating teams during the competition, except in the last hour, when the scoreboard is "frozen" and no further updates are shown. However, teams still receive instant feedback on their own submissions.
Teams may be allowed to bring printed (not electronic) reference materials to the competition floor. At the World Finals, up to 25 pages are permitted. The rules vary between regional contests; some may permit arbitrary amounts of printed material, whereas some might permit none at all.
A post-secondary institution may only participate officially in the regional contest(s) in the region in which it is located. Some regions may allow multiple teams from a single institution. The highest-scoring team from each region advances to the World Finals, but multiple teams may advance from some regions. An institution may not send multiple teams to the World Finals.