文章基本信息

标题：Polynomial Fixed-parameter Algorithms: A Case Study for Longest Path on Interval Graphs
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作者：Archontia C. Giannopoulou ; George B. Mertzios ; Rolf Niedermeier 等
期刊名称：LIPIcs : Leibniz International Proceedings in Informatics
电子版ISSN：1868-8969
出版年度：2015
卷号：43
页码：102-113
DOI：10.4230/LIPIcs.IPEC.2015.102
出版社：Schloss Dagstuhl -- Leibniz-Zentrum fuer Informatik
摘要：We study the design of fixed-parameter algorithms for problems already known to be solvable in polynomial time. The main motivation is to get more efficient algorithms for problems with unattractive polynomial running times. Here, we focus on a fundamental graph problem: Longest Path; it is NP-hard in general but known to be solvable in O(n^4) time on n-vertex interval graphs. We show how to solve Longest Path on Interval Graphs, parameterized by vertex deletion number k to proper interval graphs, in O(k^9n) time. Notably, Longest Path is trivially solvable in linear time on proper interval graphs, and the parameter value k can be approximated up to a factor of 4 in linear time. From a more general perspective, we believe that using parameterized complexity analysis for polynomial-time solvable problems offers a very fertile ground for future studies for all sorts of algorithmic problems. It may enable a refined understanding of efficiency aspects for polynomial-time solvable problems, similarly to what classical parameterized complexity analysis does for NP-hard problems.
关键词：fixed-parameter algorithm; preprocessing; data reduction; polynomial-time algorithm; longest path problem; interval graphs; proper interval vertex del