Matrix algorithm

In this problem, you start with a matrix of positive integers with $N$ rows (numbered $1$ through $N$) and $N$ columns (numbered $1$ through $N$). The algorithm proceeds in steps. In the first step, for each row of the matrix, you should find the smallest element in this row and subtract it from each element of the matrix in this row. In the second step, for each column of the matrix, you sh