An Additive Algorithm for Solving Linear Programs with Zero-One Variables

An algorithm is proposed for solving linear programs with variables constrained to take only one of the values 0 or 1. It starts by setting all the n variables equal to 0, and consists of a systematic procedure of successively assigning to certain variables the value 1, in such a way that after trying a (small) part of all the 2ⁿ possible combinations, one obtains either an optimal solution, or evidence of the fact that no feasible solution exists. The only operations required under the algorithm are additions and subtractions; thus round-off errors are excluded. Problems involving up to 15 variables can be solved with this algorithm by hand in not more than 3–4 hours. An extension of the algorithm to integer linear programming and to nonlinear programming is available, but not dealt with in this article.