Eisenbrand, Friedrich
Grandoni, Fabrizio
Rothvoss, Thomas
Schafer, Guido
Connected facility location via random facility sampling and core detouring
Journal Of Computer And System Sciences
10.1016/j.jcss.2010.02.001
76
709-726
We present a simple randomized algorithmic framework for connected facility location problems. The basic idea is as follows: We run a black-box approximation algorithm for the unconnected facility location problem, randomly sample the clients, and open the facilities serving sampled clients in the approximate solution. Via a novel analytical tool, which we term core detouring, we show that this approach significantly improves over the previously best known approximation ratios for several NP-hard network design problems. For example, we reduce the approximation ratio for the connected facility location problem from 8.55 to 4.00 and for the single-sink rent-or-buy problem from 3.55 to 2.92. The mentioned results can be derandomized at the expense of a slightly worse approximation ratio. The versatility of our framework is demonstrated by devising improved approximation algorithms also for other related problems. (C) 2010 Elsevier Inc. All rights reserved.
Connected facility location;
Approximation algorithm;
Randomized algorithm;
Network design;
Approximation Algorithms;
Network Design;
Steiner Problem;
Simpler;
2010