Fence of squares
Source: Brazil National Olympiad 2019 - level 2 - #5
November 23, 2019
combinatoricsBrazilian Math Olympiad
Problem Statement
In the picture below, a white square is surrounded by four black squares and three white squares. They are surrounded by seven black squares.
https://i.stack.imgur.com/Dalmm.png
What is the maximum number of white squares that can be surrounded by black squares?