Greedy Local Improvement and Weighted Set Packing Approximation
✍ Scribed by Barun Chandra; Magnús M Halldórsson
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 134 KB
- Volume
- 39
- Category
- Article
- ISSN
- 0196-6774
No coin nor oath required. For personal study only.
✦ Synopsis
Given a collection of weighted sets, each containing at most k elements drawn from a finite base set, the kset packing problem is to find a maximum weight subcollection of disjoint sets. A greedy algorithm for this problem approximates it to within a factor of k, and natural local search has been shown to approximate it to within a factor of roughly k -1. However, neither paradigm can yield approximations that improve on this.We present an approximation algorithm for the weighted k-set packing problem that combines the two paradigms by starting with an initial greedy solution and then repeatedly choosing the best possible local improvement. The algorithm has a performance ratio of 2(k + 1)/3, which we show is asymptotically tight. Thii is the first asymptotic improvement over the straightforward ratio of k.
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