MathDB
Rio-Challenge

Source: Rioplatense Olympiad 2016

April 2, 2018
combinatorics

Problem Statement

Initially one have the number 00 in each cell of the table 29×2929 \times 29. A moviment is when one choose a sub-table 5×55 \times 5 and add +1+1 for every cell of this sub-table. Find the maximum value of nn, where after 10001000 moviments, there are 44 cells such that your centers are vertices of a square and the sum of this 44 cells is at least nn. Note: A square does not, necessarily, have your sides parallel with the sides of the table.