Multiple String Search: Difference between revisions

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[[File:String Search - Multiple String Search - Space.png|1000px]]
[[File:String Search - Multiple String Search - Space.png|1000px]]


== Pareto Frontier Improvements Graph ==  
== Space-Time Tradeoff Improvements ==  


[[File:String Search - Multiple String Search - Pareto Frontier.png|1000px]]
[[File:String Search - Multiple String Search - Pareto Frontier.png|1000px]]

Revision as of 14:35, 15 February 2023

Description

Multiple string search algorithms try to find a place where one or several strings (also called patterns) are found within a larger string or text.

Related Problems

Related: Single String Search

Parameters

$m$: longest pattern length

$n$: length of searchable text

$s$: size of the alphabet

$k$: number of patterns to search for

$z$: number of matches

Table of Algorithms

Name Year Time Space Approximation Factor Model Reference
Commentz-Walter Algorithm 1979 $O(mn)$ $O(km)$ Exact Deterministic Time
Aho–Corasick (AC) Algorithm 1975 $O(n + m + z)$ $O(km)$ Exact Deterministic Time
Wu and Manber, Fuzzy String Matching 1992 $O(nk \lceil m/w \rceil)$ $O(ms + k \lceil m/w \rceil)$ Levensthein Distance = k Deterministic Time & Space

Time Complexity Graph

String Search - Multiple String Search - Time.png

Space Complexity Graph

String Search - Multiple String Search - Space.png

Space-Time Tradeoff Improvements

String Search - Multiple String Search - Pareto Frontier.png

References/Citation

https://cr.yp.to/bib/1975/aho.pdf