Solution
This is the cost matrix.
Subtract row minima
For each row, the minimum element is subtracted from all elements in that row.
| 11 | 37 | 0 | (-10) |
| 0 | 45 | 47 | (-49) |
| 59 | 0 | 10 | (-6) |
Subtract column minima
Because each column already contains a zero, subtracting the column minima has no effect.
Cover all zeros with a minimum number of lines
A total of 3 lines are required to cover all zeros.
The optimal assignment
Because there are 3 lines required, an optimal assignment exists among the zeros.
This corresponds to the following optimal assignment in the original cost matrix.
The total minimum cost is 65.