We present a preprocessing algorithm to make certain polynomial time algorithms strongly polynomial time. The running time of some of the known combinatorial optimization algorithms depends on the size of the objective function w. Our preprocessing algorithm replaces w by an integral valued -w whose size is polynomially bounded in the size of the combinatorial structure and which yields the same set of optimal solutions as w. As applications we show how existing polynomial time algorithms for finding the maximum weight clique in a perfect graph and for the minimum cost submodular flow problem can be made strongly polynomial. Further we apply the preprocessing technique to make H. W. Lenstra's and R. Kannan's Integer Linear Programming algorithms run in polynomial space. This also reduces the number of arithmetic operations used. The method relies on simultaneous Diophantine approximation.
- AMS subject classification (1980): 68E10
ASJC Scopus subject areas
- Discrete Mathematics and Combinatorics
- Computational Mathematics