TOT 1999 Autumn AS6 rook on a large chessboard, rectangle combo
Source:
May 11, 2020
combinatorial geometrycombinatoricsrectangleChessboard
Problem Statement
On a large chessboard of its squares have been marked such thar the rook (which moves only horizontally or vertically) can visit all the marked squares without jumpin over any unmarked ones. Prove that the figure consisting of all the marked squares can be cut into rectangles.(A Shapovalov)