A hardness result and new algorithm for the longest common palindromic subsequence problem

Shunsuke Inenaga; Heikki Hyyrö

doi:10.1016/j.ipl.2017.08.006

A hardness result and new algorithm for the longest common palindromic subsequence problem

Shunsuke Inenaga, Heikki Hyyrö

Mathematical Informatics

Research output: Contribution to journal › Article › peer-review

8 Citations (Scopus)

Abstract

The 2-LCPS problem, first introduced by Chowdhury et al. (2014) [17], asks one to compute (the length of) a longest common palindromic subsequence between two given strings A and B. We show that the 2-LCPS problem is at least as hard as the well-studied longest common subsequence problem for four strings. Then, we present a new algorithm which solves the 2-LCPS problem in O(σM²+n) time, where n denotes the length of A and B, M denotes the number of matching positions between A and B, and σ denotes the number of distinct characters occurring in both A and B. Our new algorithm is faster than Chowdhury et al.'s sparse algorithm when σ=o(log²⁡nlog⁡log⁡n).

Original language	English
Pages (from-to)	11-15
Number of pages	5
Journal	Information Processing Letters
Volume	129
DOIs	https://doi.org/10.1016/j.ipl.2017.08.006
Publication status	Published - Jan 2018

All Science Journal Classification (ASJC) codes

Theoretical Computer Science
Signal Processing
Information Systems
Computer Science Applications

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title = "A hardness result and new algorithm for the longest common palindromic subsequence problem",

abstract = "The 2-LCPS problem, first introduced by Chowdhury et al. (2014) [17], asks one to compute (the length of) a longest common palindromic subsequence between two given strings A and B. We show that the 2-LCPS problem is at least as hard as the well-studied longest common subsequence problem for four strings. Then, we present a new algorithm which solves the 2-LCPS problem in O(σM2+n) time, where n denotes the length of A and B, M denotes the number of matching positions between A and B, and σ denotes the number of distinct characters occurring in both A and B. Our new algorithm is faster than Chowdhury et al.'s sparse algorithm when σ=o(log2⁡nlog⁡log⁡n).",

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