In a 2-D matrix of m*n select m-1 elements from each row such that that the resulting sum is minimum and each column is selected atleast once.

Ex –

2 3 5

3 2 5

4 4 7

Selecting (2,3) from 1st row, (2,5) from 2nd row and (4,4) from 3rd row would result in minimum sum of 20