The International Olympiad in Informatics (IOI) is an annual competitive programming competition for secondary school students. The first IOI was held in 1989 in Pravetz, Bulgaria.
The contest consists of two days computer programming, solving problems of an algorithmic nature. Students compete on an individual basis, with up to four students competing from each participating country (with around 81 countries in 2004). Students in the national teams are selected through national computing contests, such as the Australian Informatics Olympiad, British Informatics Olympiad, and Bundeswettbewerb Informatik (Germany).
The IOI is one of the most prestigious computer science competitions in the world. UNESCO and IFIP are patrons of the International Olympiad in Informatics.
Read more about International Olympiad In Informatics: Structure of The Competition, List of IOI Websites and Locations, Multiple IOI Winners