Inspired by scaffold filling, a recent approach for genome reconstruction from incomplete data, we consider a variant of the well-known longest common subsequence problem for the comparison of two sequences. The new problem, called Longest Filled Common Subsequence, aims to compare a complete sequence with an incomplete one, i.e. with some missing elements. Longest Filled Common Subsequence (LFCS), given a complete sequence A, an incomplete sequence B, and a multiset M of symbols missing in B, asks for a sequence B⁎ obtained by inserting the symbols of M into B so that B⁎ induces a common subsequence with A of maximum length. We investigate the computational and approximation complexity of the problem and we show that it is NP-hard and APX-hard when A contains at most two occurrences of each symbol, and we give a polynomial time algorithm when the input sequences are over a constant-size alphabet. We give a [Formula presented] approximation algorithm for the Longest Filled Common Subsequence problem. Finally, we present a fixed-parameter algorithm for the problem, when it is parameterized by the number of symbols inserted in B that “match” symbols of A.

Castelli, M., Dondi, R., Mauri, G., Zoppis, I. (2019). Comparing incomplete sequences via longest common subsequence. THEORETICAL COMPUTER SCIENCE, 796, 272-285 [10.1016/j.tcs.2019.09.022].

Comparing incomplete sequences via longest common subsequence

Mauri G.
;
Zoppis I.
2019

Abstract

Inspired by scaffold filling, a recent approach for genome reconstruction from incomplete data, we consider a variant of the well-known longest common subsequence problem for the comparison of two sequences. The new problem, called Longest Filled Common Subsequence, aims to compare a complete sequence with an incomplete one, i.e. with some missing elements. Longest Filled Common Subsequence (LFCS), given a complete sequence A, an incomplete sequence B, and a multiset M of symbols missing in B, asks for a sequence B⁎ obtained by inserting the symbols of M into B so that B⁎ induces a common subsequence with A of maximum length. We investigate the computational and approximation complexity of the problem and we show that it is NP-hard and APX-hard when A contains at most two occurrences of each symbol, and we give a polynomial time algorithm when the input sequences are over a constant-size alphabet. We give a [Formula presented] approximation algorithm for the Longest Filled Common Subsequence problem. Finally, we present a fixed-parameter algorithm for the problem, when it is parameterized by the number of symbols inserted in B that “match” symbols of A.
Articolo in rivista - Articolo scientifico
Approximation algorithms; Computational complexity; Fixed-parameter algorithms; Longest common subsequence; String algorithms;
Approximation algorithms; Computational complexity; Fixed-parameter algorithms; Longest common subsequence; String algorithms
English
2019
796
272
285
reserved
Castelli, M., Dondi, R., Mauri, G., Zoppis, I. (2019). Comparing incomplete sequences via longest common subsequence. THEORETICAL COMPUTER SCIENCE, 796, 272-285 [10.1016/j.tcs.2019.09.022].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/253649
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