Publication Type

Journal Article

Version

publishedVersion

Publication Date

5-2022

Abstract

The suffix array is a fundamental data structure for many applications that involve string searching and data compression. Designing time/space-efficient suffix array construction algorithms has attracted significant attention and considerable advances have been made for the past 20 years. We obtain the \emph{first} in-place suffix array construction algorithms that are optimal both in time and space for (read-only) integer alphabets. Concretely, we make the following contributions: 1. For integer alphabets, we obtain the first suffix sorting algorithm which takes linear time and uses only $O(1)$ workspace (the workspace is the total space needed beyond the input string and the output suffix array). The input string may be modified during the execution of the algorithm, but should be restored upon termination of the algorithm. 2. We strengthen the first result by providing the first in-place linear time algorithm for read-only integer alphabets with $|\Sigma|=O(n)$ (i.e., the input string cannot be modified). This algorithm settles the open problem posed by Franceschini and Muthukrishnan in ICALP 2007. The open problem asked to design in-place algorithms in $o(n\log n)$ time and ultimately, in $O(n)$ time for (read-only) integer alphabets with $|\Sigma| \leq n$. Our result is in fact slightly stronger since we allow $|\Sigma|=O(n)$. 3. Besides, for the read-only general alphabets (i.e., only comparisons are allowed), we present an optimal in-place $O(n\log n)$ time suffix sorting algorithm, recovering the result obtained by Franceschini and Muthukrishnan which was an open problem posed by Manzini and Ferragina in ESA 2002.

Keywords

Suffix sorting, Suffix array, In-place, Optimal time

Discipline

Databases and Information Systems

Research Areas

Data Science and Engineering; Intelligent Systems and Optimization

Publication

Information and Computation

Volume

285

First Page

1

Last Page

25

ISSN

0890-5401

Identifier

10.1016/j.ic.2021.104818

Publisher

Elsevier

Additional URL

https://doi.org/10.1016/j.ic.2021.104818

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