Title
All semi-local longest common subsequences in subquadratic time
Abstract
For two strings a, b of lengths m, n respectively, the longest common subsequence (LCS) problem consists in comparing a and b by computing the length of their LCS . In this paper, we define a generalisation, called “the all semi-local LCS problem”, where each string is compared against all substrings of the other string, and all prefixes of each string are compared against all suffixes of the other string. An explicit representation of the output lengths is of size Θ ((m+n)2). We show that the output can be represented implicitly by a geometric data structure of size O(m+n), allowing efficient queries of the individual output lengths. The currently best all string-substring LCS algorithm by Alves et al. can be adapted to produce the output in this form. We also develop the first all semi-local LCS algorithm, running in time o(mn) when m and n are reasonably close. Compared to a number of previous results, our approach presents an improvement in algorithm functionality, output representation efficiency, and/or running time.
Year
DOI
Venue
2006
10.1007/11753728_36
CSR
Keywords
Field
DocType
output representation efficiency,algorithm functionality,lengths m,output length,subquadratic time,size o,string-substring lcs algorithm,individual output length,semi-local lcs algorithm,semi-local longest common subsequence,explicit representation,semi-local lcs problem,longest common subsequence
Data structure,Geometric data analysis,Discrete mathematics,Combinatorics,Substring,Longest common subsequence problem,Suffix,Generalization,Prefix,String (computer science),Mathematics
Conference
Volume
ISSN
ISBN
3967
0302-9743
3-540-34166-8
Citations 
PageRank 
References 
6
0.52
14
Authors
1
Name
Order
Citations
PageRank
Alexander Tiskin122015.50