MathDB

5

Part of 1962 All-Soviet Union Olympiad

Problems(1)

Array of numbers with 1 and -1

Source: 1962 All-Soviet Union Olympiad

1/15/2018
An n×nn \times n array of numbers is given. nn is odd and each number in the array is 11 or −1-1. Prove that the number of rows and columns containing an odd number of −1-1s cannot total nn.
Russiacombinatorics