A Linear Space Data Structure for Range LCP Queries

• Published in: Fundamenta informaticae Vol. 163; no. 3; pp. 245 - 251
• Main Authors: Ganguly, Arnab, Patil, Manish, Shah, Rahul, Thankachan, Sharma V.
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 03.11.2018; Sage Publications Ltd
• Subjects: Data structures; Entrepreneurs; Queries; Satellites; Suffix Trees; Range Query; String Algorithms
• ISSN: 0169-2968; 1875-8681
• DOI: 10.3233/FI-2018-1741

Range LCP (longest common prefix) is an extension of the classical LCP problem and is defined as follows: Preprocess a string S[1...n] of n characters, such that whenever an interval [i, j] comes as a query, we can report max{|LCP(Sp, Sq)| | i ≤ p < q ≤ j} Here LCP(Sp, Sq) is the longest common prefix of the suffixes of S starting at locations p and q, and |LCP(Sp, Sq)| is its length. This problem was first addressed by Amir et al. [ISAAC, 2011]. They showed that the query can be answered in O(log log n) time using an O(n log1+ɛn) space data structure for an arbitrarily small constant ɛ > 0. In an attempt to reduce the space bound, they presented a linear space data structure of O(d log log n) query time, where d = (j − i + 1). In this paper, we present a new linear space data structure with an improved query time of O ( d log d ( log n ) 1 / 2 − ɛ ) .