MathDB
TOT 197 1988 Autumn Train S4 min no of good pair of colours

Source:

March 7, 2021
Coloringcombinatorial geometrycombinatorics

Problem Statement

A page of an exercise book is painted with 2323 colours, arranged in squares. A pair of colours is called good if there are neighbouring squares painted with these colours. What is the minimum number of good pairs?