Space-time Trade-offs for the LCP Array of Wheeler DFAs

Fuente: arXiv
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Main Authors: Cotumaccio, Nicola, Gagie, Travis, Köppl, Dominik, Prezza, Nicola
Format: Preprint
Published: 2023
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author Cotumaccio, Nicola
Gagie, Travis
Köppl, Dominik
Prezza, Nicola
author_facet Cotumaccio, Nicola
Gagie, Travis
Köppl, Dominik
Prezza, Nicola
contents Recently, Conte et al. generalized the longest-common prefix (LCP) array from strings to Wheeler DFAs, and they showed that it can be used to efficiently determine matching statistics on a Wheeler DFA [DCC 2023]. However, storing the LCP array requires $ O(n \log n) $ bits, $ n $ being the number of states, while the compact representation of Wheeler DFAs often requires much less space. In particular, the BOSS representation of a de Bruijn graph only requires a linear number of bits, if the size of alphabet is constant. In this paper, we propose a sampling technique that allows to access an entry of the LCP array in logarithmic time by only storing a linear number of bits. We use our technique to provide a space-time trade-off to compute matching statistics on a Wheeler DFA. In addition, we show that by augmenting the BOSS representation of a $ k $-th order de Bruijn graph with a linear number of bits we can navigate the underlying variable-order de Bruijn graph in time logarithmic in $ k $, thus improving a previous bound by Boucher et al. which was linear in $ k $ [DCC 2015].
format Preprint
id arxiv_https___arxiv_org_abs_2306_05684
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Space-time Trade-offs for the LCP Array of Wheeler DFAs
Cotumaccio, Nicola
Gagie, Travis
Köppl, Dominik
Prezza, Nicola
Data Structures and Algorithms
Recently, Conte et al. generalized the longest-common prefix (LCP) array from strings to Wheeler DFAs, and they showed that it can be used to efficiently determine matching statistics on a Wheeler DFA [DCC 2023]. However, storing the LCP array requires $ O(n \log n) $ bits, $ n $ being the number of states, while the compact representation of Wheeler DFAs often requires much less space. In particular, the BOSS representation of a de Bruijn graph only requires a linear number of bits, if the size of alphabet is constant. In this paper, we propose a sampling technique that allows to access an entry of the LCP array in logarithmic time by only storing a linear number of bits. We use our technique to provide a space-time trade-off to compute matching statistics on a Wheeler DFA. In addition, we show that by augmenting the BOSS representation of a $ k $-th order de Bruijn graph with a linear number of bits we can navigate the underlying variable-order de Bruijn graph in time logarithmic in $ k $, thus improving a previous bound by Boucher et al. which was linear in $ k $ [DCC 2015].
title Space-time Trade-offs for the LCP Array of Wheeler DFAs
topic Data Structures and Algorithms
url https://arxiv.org/abs/2306.05684