Skip to Main content Skip to Navigation
Journal articles

Exemplar Longest Common Subsequence

Abstract : In this paper, we investigate the computational and approximation complexity of the Exemplar Longest Common Subsequence of a set of sequences (ELCS problem), a generalization of the Longest Common Subsequence problem, where the input sequences are over the union of two disjoint sets of symbols, a set of mandatory symbols and a set of optional symbols. We show that different versions of the problem are APX-hard even for instances with two sequences. Moreover, we show that the related problem of determining the existence of a feasible solution of the Exemplar Longest Common Subsequence of two sequences is NP-hard. On the positive side, we first present an efficient algorithm for the ELCS problem over instances of two sequences where each mandatory symbol can appear in total at most three times in the sequences. Furthermore, we present two fixed parameter algorithms for the ELCS problem over instances of two sequences where the parameter is the number of mandatory symbols.
Complete list of metadata
Contributor : Guillaume Fertin Connect in order to contact the contributor
Submitted on : Wednesday, September 16, 2009 - 4:48:07 PM
Last modification on : Saturday, January 15, 2022 - 3:56:40 AM
Long-term archiving on: : Tuesday, June 15, 2010 - 11:46:15 PM


Files produced by the author(s)


  • HAL Id : hal-00417728, version 1


Paola Bonizzoni, Gianluca Della Vedova, Riccardo Dondi, Guillaume Fertin, Rafaella Rizzi, et al.. Exemplar Longest Common Subsequence. ACM Transactions on Computational Logic, Association for Computing Machinery, 2007, 4 (4), pp.535-543. ⟨hal-00417728⟩



Les métriques sont temporairement indisponibles