Winning Strategy
Source: Cono Sur Olympiad 2016, problem 3
August 28, 2017
combinatoricscono sur
Problem Statement
There are positions marked around a circle, with a token on one of them. A legitimate move is to move the token either 1 position or 4 positions from its location, clockwise. The restriction is that the token can not occupy the same position more than once. Players and take turns making moves. Player has the first move. The first player who cannot make a legitimate move loses. Determine which of the two players has a winning strategy.