COCI

COCI stands for the Croatian Open Competition in Informatics. It is an annual competitive programming contest for high school students in Croatia and the surrounding region. Since its inception in the late 1990s, it has become the country’s leading arena for training young programmers and for identifying talent for international contests. The competition is organized by Croatian educational and computer science communities and reaches a national scale through schools and clubs.

The contest consists of a series of online rounds throughout the school year, culminating in a final round typically held in Croatia. In each round, participants work to implement efficient algorithms to solve a set of problems within strict time and memory limits. Submissions are evaluated by an automated judge that verifies correctness and performance. Contestants may use a variety of programming languages, with C++, Java, and other common languages supported by the judge.

Top performers receive medals and sometimes scholarships or internships. COCI also serves as the main route for selecting Croatia’s team for the International Olympiad in Informatics (IOI). Over the years, the competition has helped to cultivate a community of competitive programmers in Croatia and the region, contributing to education, research, and industry.