MathDB
Romania Junior TST 2021 Day 1 P4

Source:

May 16, 2021
combinatoricsRomanian TSTTST

Problem Statement

Let n2n\geq 2 be a positive integer. On an n×nn\times n board, nn rooks are placed in such a manner that no two attack each other. All rooks move at the same time and are only allowed to move in a square adjacent to the one in which they are located. Determine all the values ​​of nn for which there is a placement of the rooks so that, after a move, the rooks still do not attack each other.
Note: Two squares are adjacent if they share a common side.