In one method for determining a minimum cost solution for resolving a covering-by-pairs problem, a plurality of covering nodes, a plurality of branch nodes, and a plurality of edges connecting the covering nodes and the branch nodes are given. A plurality of vectors are generated. For each vector in the plurality of vectors, it is determined whether the selected covering nodes cover the branch nodes. Responsive to determining that the selected covering nodes do not cover the branch nodes, each vector is completed so that the selected covering nodes cover the branch nodes. Responsive to determining that selected covering nodes cover the branch nodes or to completing the vector, redundant covering nodes are removed from each vector. The vectors are inserted into a current population. A new population is generated by evolving the current population for at least one generation.