2009 × 4018 rectangular board - [UKRMO 2009 Grade 8]
Source:
January 21, 2011
geometryrectangle
Problem Statement
Given rectangular board. Frame is a rectangle or for without all cells which don’t have any common points with boundary of rectangle. Rectangles and are also frames. Two players by turn paint all cells of some frame that has no painted cells yet. Player that can't make such move loses. Who has a winning strategy?