Chessboards
Source:
October 9, 2005
rectanglefloor functioninductioncombinatorics proposedcombinatoricsExtremal combinatoricsHi
Problem Statement
A computer screen shows a chessboard, colored in the usual way. One can select with a mouse any rectangle with sides on the lines of the chessboard and click the mouse button: as a result, the colors in the selected rectangle switch (black becomes white, white becomes black). Find, with proof, the minimum number of mouse clicks needed to make the chessboard all one color.