2 player game, k coins on intersections of n lines
Source: Rioplatense 2022 L3 p5
December 20, 2022
combinatoricsgame strategywinning strategygame
Problem Statement
Let and be positive integers. We consider lines in the plane between which there are not two parallel nor three concurrent. In each of the points of intersection of these lines, coins are placed. Ana and Beto play the following game in turns: each player, in turn, chooses one of those points that does not share one of the lines with the point chosen immediately before by the other player, and removes a coin from that point. Ana starts and can choose any point. The player who cannot make his move loses. Determine based on and who has a winning strategy.