Approximately Covering Vertices by Order-5 or Longer Paths
摘要
This paper studies \(MPC^{5+}_v\) , which is to cover as many vertices as possible in a given graph \(G=(V,E)\) by vertex-disjoint \(5^+\) -paths (i.e., paths each with at least five vertices). \(MPC^{5+}_v\) is NP-hard and admits an existing local-search-based approximation algorithm which achieves a ratio of \(\frac{19}{7}\approx 2.714\) and runs in \(O(|V|^6)\) time. In this paper, we present a new approximation algorithm for \(MPC^{5+}_v\) which achieves a ratio of 2.511 and runs in \(O(\max \{|E|^2|V|^{2.5}, |E||V|^4\})\) time. Unlike the previous algorithm, the new algorithm is based on maximum matching, maximum path-cycle cover, and recursion.