MathDB
Difference between number of red & blue integers ≤ 1000

Source: Itamo 2013, problem 3

May 17, 2013
absolute valuecombinatorics proposedcombinatorics

Problem Statement

Each integer is colored with one of two colors, red or blue. It is known that, for every finite set AA of consecutive integers, the absolute value of the difference between the number of red and blue integers in the set AA is at most 10001000. Prove that there exists a set of 20002000 consecutive integers in which there are exactly 10001000 red numbers and 10001000 numbers blue.