Score Inflation The more points students score in our contests, the happier we here at the USACO are. We try to design our contests so that people can score as many points as possible, and would li

Humble Numbers For a given set of K prime numbers S = {p1, p2, ..., pK}, consider the set of all numbers whose prime factors are a subset of S. This set contains, for example, p1, p1p2, p1p1, and

Contact IOI'98 The cows have developed a new interest in scanning the universe outside their farm with radiotelescopes. Recently, they noticed a very curious microwave pulsing emission sent right fr

Stringsobits Kim Schrijvers Consider an ordered set S of strings of N (1 This set of strings is interesting because it is ordered and contains all possible strings of length N that have L (1 You

Longest Prefix IOI'96 The structure of some biological objects is represented by the sequence of their constituents, where each part is denote by an uppercase letter. Biologists are interested in de

Cow Pedigrees Silviu Ganceanu -- 2003 Farmer John is considering purchasing a new herd of cows. In this new herd, each mother cow gives birth to two children. The relationships among the cows ca

Money Systems The cows have not only created their own government but they have chosen to create their own money system. In their own rebellious way, they are curious about values of coinage. Tradi