2023 China TST Problem 9
Source: 2023 China TST Problem 9
March 18, 2023
combinatoricsChina TST
Problem Statement
Find the largest positive integer which makes it possible to color several cells of a table red such that [*] There are no two red cells satisfying: the two rows in which they are have the same number of red cells, while the two columns in which they are also have the same number of red cells; [*] There are two rows with exactly red cells each.