| Affiliation: | (1) One Microsoft Way, Redmond, WA 98007, USA;(2) College of Computing, Georgia Institute of Technology, Atlanta, GA 30332–0280, USA |
| Abstract: | We consider a fault tolerant version of the metric facility location problem in which every city, j, is required to be connected to r j facilities. We give the first non-trivial approximation algorithm for this problem, having an approximation guarantee of 3 · H k , where k is the maximum requirement and H k is the kth harmonic number. Our algorithm is along the lines of [2] for the generalized Steiner network problem. It runs in phases, and each phase, using a generalization of the primal–dual algorithm of [5] for the metric facility location problem, reduces the maximum residual requirement by one. |
