MathDB

In a tennis tournament there are participants from

n

different countries. Each team consists of a coach and a player whom should settle in a hotel. The rooms considered for the settlement of coaches are different from players' ones. Each player wants to be in a room whose roommates are all from countries which have a defense agreement with the player's country. Conversely, each coach wants to be in a room whose roommates are all from countries which don't have a defense agreement with the coach's country. Find the minimum number of the rooms such that we can always grant everyone's desire.
proposed by Seyed Reza Hosseini and Mohammad Amin Ghiasi

Problem Statement