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Logarithmic-Time Internal Pattern Matching Queries in Compressed and Dynamic Texts

Anouk Duyster
Max-Planck-Institut für Informatik - D1
AG1 Mittagsseminar (own work)
AG 1  
AG Audience
English

Date, Time and Location

Thursday, 12 September 2024
13:00
30 Minutes
E1 4
024
Saarbrücken

Abstract

Internal Pattern Matching (IPM) queries on a text T, given two fragments X and Y of T such that |Y|<2|X|, ask to compute all exact occurrences of X within Y. IPM queries have been introduced by Kociumaka, Radoszewski, Rytter, and Waleń [SODA'15], who showed that they can be answered in O(1) time using a data structure of size O(n) and used this result to answer various queries about fragments of T.


In this work, we study IPM queries on compressed and dynamic strings. Our result is an O(log n)-time query algorithm applicable to any balanced recompression-based run-length straight-line program (RLSLP).
In particular, one can use it on top of the RLSLP of Kociumaka, Navarro, and Prezza [IEEE TIT'23], whose size O(δ log (n * log σ)/(δ log n)) is optimal (among all text representations) as a function of the text length n, the alphabet size σ, and the substring complexity δ.
Our procedure does not rely on any preprocessing of the underlying RLSLP, which makes it readily applicable on top of the dynamic strings data structure of Gawrychowski, Karczmarz, Kociumaka, Łącki and Sankowski [SODA'18], which supports fully persistent updates in logarithmic time with high probability.

This talk is based on a joint paper with Tomasz Kociumaka; and the preparation for presenting that paper at SPIRE'2024.

Contact

Nidhi Rathi
+49 681 9325 1134
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Virtual Meeting Details

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Nidhi Rathi, 09/11/2024 09:20
Nidhi Rathi, 08/13/2024 09:40
Nidhi Rathi, 08/13/2024 09:39 -- Created document.