I have learn DP recently. I am practicing DP in this OJ. Now, I am stuck on this problem.

In this problem I have to find the maximum summation of cells such that any two cells don't have the same row or column.

So, I will use recursion from top of the matrix. When using recursion I got to check if that cell is available or not, i.e. that cells row and column has not previously been used. How can I do that?