11.4

Part of 2002 All-Russian Olympiad Regional Round

Problems(1)

exists a column colored in n colors - All-Russian MO 2002 Regional (R4) 11.4

Source:

Each cell of the checkered plane is colored in one of

n^2

colors so that in any square of

n \times n

cells all colors occur. It is known that in some line all the colors occur. Prove that there exists a column colored in exactly

n

combinatoricsColoring