KMP algorithm Learning record----Jake Boxer Blog Learning Section

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Jake Boxer English blog post link: http://jakeboxer.com/blog/2009/12/13/the-knuth-morris-pratt-algorithm-in-my-own-words/

How to use partial match tables

1. Function: Use partial match table to skip the old comparison part that has already been done, starting from the non-repeating match part.

2.if (match table result greater than 1)

{

Number of characters allowed to skip = match Length-partial match table [match length-1];

}

Else

{

Number of characters allowed to skip = partial match table [match length-1];

}

To illustrate:

Use "ABABABCA" as a substring to match the "Bacbababaabcbab" string.

Some of the matching tables are as follows:

String A|b|a|b|a|b|c|a

Index value 0|1|2|3|4|5|6|7

Match value 0|0|1|2|3|4|0|1

First time match

Bacbababaabcbab

Abababca

Result: No matching results

Second match

Bacbababaabcbab

Abababca

Result: The number of matches is: 1

Number of characters allowed to skip = partial match table [1-1] = 0;

Fifth time Matching

Bacb|ababa|abcbab

|ababa|bca

Result: The number of matches is: 5

Number of characters allowed to skip = 5-Partial match table [5-1] = 5-3 = 2;

Sixth time Matching

Bacbab|aba|abcbab

Xx|aba|babca

After skipping two characters, the match result is as above, this match result is: 3

Number of characters allowed to skip = 3-Partial match table [3-1] = 3-1 = 2;

Seventh time Matching

Bacbabab|a|abcbab

Xx|a|bababca

After skipping two characters, the match result is as above, this match result is: 1

At this point, the tail character of the substring has exceeded the length of the main string, so there is no matching result between the main string and the substring.

The next article is the KMP algorithm analysis of the big liar data structure.

KMP algorithm Learning record----Jake Boxer Blog Learning Section