The International Olympiad in Informatics (IOI) is an annual informatics 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).

Structure of the competition

On each of the two competition days, the students are typically given three problems which they have to solve in five hours. Each student works on his/her own, with only a computer and no other help allowed, specifically no communication with other contestants, books etc. Usually to solve a task the contestant has to write a computer program (in C, C++ or Pascal) and submit it before the five hour competition time ends. Later on, the program is graded by being run with secret test data, consisting of multiple (typically 10 or 20) test cases. The contestant is awarded points for each test case that his program solves correctly, and within the given time and memory limit. In some cases, the contestant's program has to interact with a secret computer library, which allows problems where the input is not fixed, but depends on the program's actions - for example in game problems. Another new type of problems has known inputs which are publicly available already during the five hours of the contest. For these, the contestants have to submit the according output file instead of a program, and it is up to them whether they obtain the output files by writing a program (possibly exploiting special characteristics of the input), or by hand, or by a combination of these means.

The scores from the two competition days and all problems are summed up separately for each contestant. At the awarding ceremony, contestants are awarded medals depending on their relative total score. The top 50% of the contestants (i.e. two per country, on average) are awarded medals, such that the relative number of gold : silver : bronze : no medal is approximately 1:2:3:6 (thus 1/12 of the contestants get a gold medal).

Unlike other science olympiads, the IOI regulations specifically prohibit ranking by countries. Although unofficial rankings are circulated within some participating nations, there is therefore no standard.

List of IOI websites and locations

• IOI 2012 will be held in Milan, Italy, 2012
• IOI 2011 will be held in Thailand, 2011
• IOI 2010 will be held in Waterloo, Ontario, Canada, 2010
• IOI 2009 will be held in Plovdiv, Bulgaria, 2009
• IOI 2008 was held in Cairo, Egypt, August 16 - 23, 2008
• IOI 2007 was held in Zagreb, Croatia, August 15 - 22, 2007 (results)
• IOI 2006 was held in Mérida, Yucatán, Mexico, August 13 - 20, 2006
• IOI 2005 was held in Nowy Sącz, Poland, August 18 - 25, 2005 (results)
• IOI 2004 was held in Athens, Greece, September 11 - 18, 2004 (results)
• IOI 2003 was held in Kenosha, Wisconsin, USA, August 16 - 23, 2003 (results)
• IOI 2002 was held in Yong-In, Republic of Korea, August 18 - 25, 2002
• IOI 2001 was held in Tampere, Finland, July 14 - 21, 2001
• IOI 2000 was held in Beijing, People's Republic of China, September 23 - 30, 2000
• IOI 1999 was held in Antalya-Belek, Turkey, October 9 - 16, 1999
• IOI 1998 was held in Setúbal, Portugal, September 5 - 12, 1998
• IOI 1997 was held in Cape Town, South Africa, November 30 - December 7, 1997
• IOI 1996 was held in Veszprém, Hungary, July 25 - August 2, 1996
• IOI 1995 was held in Eindhoven, The Netherlands, June 26 - July 3, 1995
• IOI 1994 was held in Haninge, Sweden, July 3 - 10, 1994
• IOI 1993 was held in Mendoza, Argentina, October 16 - 25, 1993
• IOI 1992 was held in Bonn, Germany, July 11 - 21, 1992
• IOI 1991 was held in Athens, Greece, May 19 - 25, 1991
• IOI 1990 was held in Minsk, Belarusian SSR, Soviet Union, July 15 - 21, 1990
• IOI 1989 was held in Pravetz, Bulgaria, May 16 - 19, 1989.

Multiple IOI winners

The following is a list of the top 21 performers in the history of the IOI. First (I), second (II) and third (III) places among gold medalists are indicated where appropriate. This list includes only those countries where the national selection contest allows the same participant to go multiple times to the IOI.

Name	Team	Years
Filip Wolski	Poland	G(I) 2006	G 2005	G 2004	G 2003
Reid Barton	United States	G(I) 2001	G 2000
Martin Pettai	Estonia	G 2002	G 2001	G 2000	S 1999
Andrzej Gasienica-Samek	Poland	G 1999	G 1998	G 1997	S 1996
Vladimir Martianov	Russia	G 1999	G(I) 1998	G(I) 1997
Martin Mares	Czech Republic	G 1995	G 1994	G 1993
John Pardon	United States	G 2007	G 2006	G 2005
Marcin Andrychowicz	Poland	G 2008	G 2007	G 2006
Bruce Merry	South Africa	G 2001	G 2000	S 1999	B 1998	B 1997	B 1996
Alex Schwendner	United States	G 2005	G 2003	S 2004	S 2002
Wolfgang Thaller	Austria	G 1997	G 1996	S 1999	S 1998
Victor Bargachev	Russia	G(I) 1995	G(I) 1994	S 1993
Mihai Patrascu	Romania	G(II) 2001	G 2000	S 1999
Roman Pastoukhov	Russia	G 2000	G(II) 1999	S 2001
Piotr Zieliński	Poland	G 1997	G(III) 1996	S 1995
Miroslav Dudik	Slovakia	G 1997	G 1996	S 1995
Richard Kralovic	Slovakia	G 1999	G 1998	S 1997
Tomasz Czajka	Poland (1998, 2000), United Kingdom (1999)	G 2000	G 1999	S 1998
Petr Mitrichev	Russia	G 2002	G 2000	S 2001
Luka Kalinovcic	Croatia	G 2004	G 2003	S 2002
Rostislav Rumenov	Bulgaria	G 2007	G 2006	S 2005
Henadzi Karatkevich	Belarus	G 2008	G 2007	S 2006
Goran Žužić	Croatia	G 2008	G 2007	B 2006

See also

• International Science Olympiad
• ACM International Collegiate Programming Contest
• Central European Olympiad in Informatics

External links

• IOI International Committee Website
• IOI Secretariat Website
• IOI 2004 (held in Athens,Greece) website
• IOI 2005 Website
• IOI 2007 Website
• IOI 2008 Website
• Photos from some former Informatics Olympiads.
• Egyptian Olympiad in Informatics