MathDB

A chessboard

1000 \times 1000

is covered by dominoes

1 \times 10

that can be rotated. We don't know which is the cover, but we are looking for it. For this reason, we choose a few

N

cells of the chessboard, for which we know the position of the dominoes that cover them. Which is the minimum

N

such that after the choice of

N

and knowing the dominoed that cover them, we can be sure and for the rest of the cover?
(Bulgaria)

Problem Statement