n = 8; a = [| 0, 1, 0, 1, 0, 0, 0, 0 | 0, 1, 0, 0, 0, 1, 0, 0 | 0, 0, 0, 0, 0, 0, 0, 1 | 0, 0, 0, 0, 1, 0, 0, 0 | 0, 0, 0, 0, 0, 0, 0, 0 | 1, 0, 0, 0, 0, 0, 1, 0 | 1, 0, 0, 1, 0, 0, 0, 1 | 0, 0, 0, 0, 1, 0, 0, 0 |]; row_sums = [3, 1, 1, 0, 2, 1, 0, 4]; col_sums = [2, 2, 1, 1, 1, 2, 1, 2];