Question 9
Jerry places at most one rook in each cell of a $2025 \times 2025$ grid of cells. A rook attacks another rook if the two rooks are in the same row or column and there are no other rooks between them.
Determine, with proof, the maximum number of rooks Jerry can place on the grid such that no rook attacks 4 other rooks.
Determine, with proof, the maximum number of rooks Jerry can place on the grid such that no rook attacks 4 other rooks.