2019 Greece National Olympiad Q4
Source: 2019 Greece National Olympiad
March 11, 2019
combinatorics
Problem Statement
Given a grid we play the following game . Initially we place tokens in each of empty cells and at the end of the game we need to fill the whole grid with tokens.For that purpose we are allowed to make the following move:If an empty cell shares a common side with at least two other cells that contain a token then we can place a token in this cell.Find the minimum value of in terms of that enables us to win the game.