blogspot.software_and_algorithms.stern_library.string

Class KnuthMorrisPrattAlgorithm

java.lang.Object

blogspot.software_and_algorithms.stern_library.string.KnuthMorrisPrattAlgorithm

public class KnuthMorrisPrattAlgorithm
extends Object

An implementation of the Knuth Morris Pratt substring search algorithm. An instance of the algorithm is constructed around a needle string of length m, a process which consumes O(m) time as well as O(m) space. Once an instance is constructed, it is capable of searching for the needle string in any number of haystack strings. The search process consumes O(n) time in a haystack string of length n.

Author:

Kevin L. Stern

Constructor Summary

Constructors

Constructor and Description
KnuthMorrisPrattAlgorithm(String needle) Constructor.

Method Summary

Modifier and Type	Method and Description
int	execute(String haystack) Execute the search algorithm.
int	execute(String haystack, int index) Execute the search algorithm.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

KnuthMorrisPrattAlgorithm

public KnuthMorrisPrattAlgorithm(String needle)

Constructor.

Parameters:

needle - the search string for which the instance will be constructed.

Method Detail

execute

public int execute(String haystack)

Execute the search algorithm.

Parameters:

haystack - the string in which to search for the needle specified at construction time.

Returns:

the index of the first occurrence of the needle string within the specified haystack string, -1 if none.

execute

public int execute(String haystack,
                   int index)

Execute the search algorithm.

Parameters:

haystack - the string in which to search for the needle specified at construction time.

index - the index at which to begin the search within the haystack string.

Returns:

the index of the first occurrence of the needle string within the specified portion of the haystack string, -1 if none.