Killjoy and matrix

In a game of Valorant, Killjoy is a defensive expert. She is famous for her grenade capabilities. Now there is a challenging map called Haven. Haven is divided into $N*N$ blocks and Killjoy want to destroy all the blocks using her grenades. She placed a grenade in each block with power $P_{ij}$ ($i$ denotes the row and $j$ denotes the column of that block). A grenade with power $y$ will not e