Packed Acyclic Deterministic Finite Automata

Hiroki Shibata, Masakazu Ishihata, Shunsuke Inenaga

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

An acyclic deterministic finite automaton (ADFA) is a data structure that represents a set of strings (i.e., a dictionary) and facilitates a pattern-searching problem of determining whether a given pattern string is present in the dictionary. We introduce the packed ADFA (PADFA), a compact variant of ADFA designed to achieve more efficient pattern searching by encoding specific paths as packed strings stored in contiguous memory. We theoretically demonstrate that pattern searching in PADFA is near time-optimal with a small additional overhead and becomes fully time-optimal for sufficiently long patterns. Moreover, we prove that a PADFA requires fewer bits than a trie when the dictionary size is relatively smaller than the number of states in the PADFA. Lastly, we empirically show that PADFAs improve both the space and time efficiency of pattern searching on real-world datasets.

Original languageEnglish
Title of host publicationSOFSEM 2025
Subtitle of host publicationTheory and Practice of Computer Science - 50th International Conference on Current Trends in Theory and Practice of Computer Science, SOFSEM 2025, Proceedings
EditorsRastislav Královič, Věra Kůrková
PublisherSpringer Science and Business Media Deutschland GmbH
Pages284-297
Number of pages14
ISBN (Print)9783031826962
DOIs
Publication statusPublished - 2025
Event50th International Conference on Current Trends in Theory and Practice of Computer Science, SOFSEM 2025 - Bratislava, Slovakia
Duration: Jan 20 2025Jan 23 2025

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume15539 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference50th International Conference on Current Trends in Theory and Practice of Computer Science, SOFSEM 2025
Country/TerritorySlovakia
CityBratislava
Period1/20/251/23/25

All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • General Computer Science

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