Toggling most of rows and columns to get chessboard coloring
Source: St Petersburg 2021 11.2
December 23, 2021
combinatoricsgrid
Problem Statement
The cells of a table are colored white. In one move, it is allowed to select some cells from the same row or column and recolor each of them with the opposite color. What is the smallest number of moves needed to get a table with a chessboard coloring?S. Berlov