MathDB
Color graph

Source: St Petersburg Olympiad 2009, Grade 11, P6

August 30, 2017
combinatoricsgraph theory

Problem Statement

Some cities in country are connected by road, and from every city goes 2008\geq 2008 roads. Every road is colored in one of two colors. Prove, that exists cycle without self-intersections ,where 504\geq 504 roads and all roads are same color.