Informatics olympiads: Approaching mathematics through code

Many readers are familiar with the International Mathematical Olympiad (IMO), a pinnacle in the yearly calendar of mathematics competitions. Here we introduce its cousin in computer science, the International Olympiad in Informatics (IOI). The International Olympiad in Informatics is one of the newer Science Olympiads, beginning in 1989 in Bulgaria under the leadership of Petar Kenderov. In its short lifespan it has also become one of the largest, with 74 countries participating in 2006 [16]. Like the IMO, the competition is targeted at secondary school students who compete on an individual basis. In this paper we take the reader on a brief tour of the IOI, paying particular attention to its relationships with traditional mathematics competitions. We begin in Section 1 with the structure of a typical IOI problem, including an outline of the mathematical ideas that lie behind such problems. For illustration, two problems are worked through in detail in Section 2. In Section 3 we compare the different ways in which mathematics and informatics contests encourage students to think mathematically. Section 4 closes with suggestions for students and teachers who wish to become involved in the IOI. It should be noted that the IOI is not the only international competition of this type. Other examples include the ACM International Collegiate Programming Contest for university students [1], and the privately-run TopCoder contests [14]. For an overview and comparison of these and related competitions, see [7]. Thanks must go to Margot Phillipps, the IOI team leader for New Zealand, for her valuable comments on an earlier draft of this paper.