MathDB
Least Changes to Make Sums Different

Source: Germany TST 2012 P1

April 13, 2020
combinatorics

Problem Statement

Find the least integer kk such that for any 2011×20112011 \times 2011 table filled with integers Kain chooses, Abel be able to change at most kk cells to achieve a new table in which 40224022 sums of rows and columns are pairwise different.