MathDB
Permuting numbers in a table

Source: Caucasus MO 2024, Juniors P6

March 15, 2024
combinatorics

Problem Statement

The integers from 11 to 320000320000 are placed in the cells of a 8×400008 \times 40000 board. Prove that it is possible to permute the rows of the table so that the numbers in each column will not be sorted from the top to the bottom in increasing order.