MathDB
PAMO 2016 Q6

Source: PAMO 2016

April 29, 2016
combinatoricssquare gridparallelogram

Problem Statement

Consider an n×nn\times{n} grid formed by n2n^2 unit squares. We define the centre of a unit square as the intersection of its diagonals. Find the smallest integer mm such that, choosing any mm unit squares in the grid, we always get four unit squares among them whose centres are vertices of a parallelogram.