Transitioning between admissible coloring
Source: Saint Petersburg 2016
December 11, 2016
combinatoricsColoring
Problem Statement
The cells of a square table are colored in one of two colors, black or white. A coloring is called admissible if for any row or column, the number of black colored cells satisfies . It is permitted to recolor a cell if by doing so the resulting configuration is still admissible. Prove that one can transition from any admissible coloring of the board to any other using a sequence of valid recoloring operations.