1000 balls in 40 different colours, 25 balls of each colour, in a circle
Source: Dutch BxMO TST 2018 p1
August 24, 2019
combinatoricscircleColoring
Problem Statement
We have balls in different colours, balls of each colour. Determine the smallest for which the following holds: if you place the balls in a circle, in any arbitrary way, then there are always adjacent balls which have at least different colours.