coloring 111^2 points
Source: Rioplatense 1999 L3 P3
September 19, 2022
combinatoricsColoringgamecombinatorial geometry
Problem Statement
Two players and play the following game:
chooses a point, with integer coordinates, on the plane and colors it green, then chooses points of integer coordinates, not yet colored, and colors them yellow. The game always continues with the same rules; and choose one and ten uncolored points and color them green and yellow, respectively.
a. The objective of is to achieve green points that are the intersections of horizontal lines and vertical lines (parallel to the coordinate axes). 's goal is to stop him. Determine which of the two players has a strategy that ensures you achieve your goal.
b. The objective of is to achieve green points that are the vertices of a square with sides parallel to the coordinate axes. 's goal is to stop him. Determine which of the two players has a strategy that will ensure that they achieve their goal.