https://github.com/titsuki/p6-algorithm-manacher

A perl6 implementation of the extended Manacher's Algorithm for solving longest palindromic substring(i.e. palindrome) problem
https://github.com/titsuki/p6-algorithm-manacher

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A perl6 implementation of the extended Manacher's Algorithm for solving longest palindromic substring(i.e. palindrome) problem

• Host: GitHub
• URL: https://github.com/titsuki/p6-algorithm-manacher
• Owner: titsuki
• License: artistic-2.0
• Created: 2016-03-30T15:11:40.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2018-11-08T15:44:48.000Z (about 6 years ago)
• Last Synced: 2024-11-05T21:50:28.122Z (about 2 months ago)
• Language: Perl 6
• Homepage:
• Size: 15.6 KB
• Stars: 1
• Watchers: 2
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: Changes
  • License: LICENSE

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README

        
[![Build Status](https://travis-ci.org/titsuki/p6-Algorithm-Manacher.svg?branch=master)](https://travis-ci.org/titsuki/p6-Algorithm-Manacher)

NAME

====

Algorithm::Manacher - A perl6 implementation of the extended Manacher's Algorithm for solving longest palindromic substring(i.e. palindrome) problem

SYNOPSIS

========

    use Algorithm::Manacher;

    # "たけやぶやけた" is one of the most famous palindromes in Japan.

    # It means "The bamboo grove was destroyed by a fire." in English.

    my $manacher = Algorithm::Manacher.new(text => "たけやぶやけた");

    $manacher.is-palindrome(); # True

    $manacher.find-longest-palindrome(); # {"たけやぶやけた" => [0]};

    $manacher.find-all-palindrome(); # {"た" => [0, 6], "け" => [1, 5], "や" => [2, 4], "たけやぶやけた" => [0]}

DESCRIPTION

===========

Algorithm::Manacher is a perl6 implementation of the extended Manacher's Algorithm for solving longest palindromic substring problem. A palindrome is a sequence which can be read same from left to right and right to left. In the original Manacher's paper [0], his algorithm has some limitations(e.g. couldn't handle a text of even length). Therefore this module employs the extended Manacher's Algorithm in [1], it enables to handle a text of both even and odd length, and compute all palindromes in a given text.

CONSTRUCTOR

-----------

    my $manacher = Algorithm::Manacher.new(text => $text);

METHODS

-------

### find-all-palindrome

    Algorithm::Manacher.new(text => "たけやぶやけた").find-all-palindrome(); # {"た" => [0, 6], "け" => [1, 5], "や" => [2, 4], "たけやぶやけた" => [0]}

Finds all palindromes in a text and returns a hash containing key/value pairs, where key is a palindromic substring and value is an array of its starting positions. If there are multiple palindromes that share the same point of symmetry, it remains the longest one.

### is-palindrome

    Algorithm::Manacher.new(text => "たけやぶやけた").is-palindrome(); # True

    Algorithm::Manacher.new(text => "たけやぶやけたわ").is-palindrome(); # False

    Algorithm::Manacher.new(text => "Perl6").is-palindrome(); # False

Returns whether a given text is a palindrome or not.

### find-longest-palindrome

    Algorithm::Manacher.new(text => "たけやぶやけた").find-longest-palindrome(); # {"たけやぶやけた" => [0]};

    Algorithm::Manacher.new(text => "たけやぶやけた。、だんしがしんだ").find-longest-palindrome(), {"たけやぶやけた" => [0], "だんしがしんだ" => [9]};

Returns the longest palindrome. If there are many candidates, it returns all of them.

AUTHOR

======

titsuki 

COPYRIGHT AND LICENSE

=====================

Copyright 2016 titsuki

This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.

This algorithm is from

  * [0] Manacher, Glenn. "A New Linear-Time``On-Line''Algorithm for Finding the Smallest Initial Palindrome of a String." Journal of the ACM (JACM) 22.3 (1975): 346-351.

  * [1] Tomohiro, I., et al. "Counting and verifying maximal palindromes." String Processing and Information Retrieval. Springer Berlin Heidelberg, 2010.