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Copy pathKMP.cpp
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68 lines (63 loc) · 1.41 KB
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//
// KMP.cpp
// Algorithm-Linux
//
// Created by SanQ11iang Zhao on 12/5/12.
// Copyright (c) 2012 SanQ11iang Zhao. All rights reserved.
//
/*
int n = KmpSearch("ababababaaabab", "abab");
std::cout<<n;
*/
#include "KMP.h"
int KmpSearch(char * text, char * pattern)
{
unsigned long length = strlen(text), pattern_length = strlen(pattern);
int count = 0, pos,i=0;
int * table = KmpNext(pattern);
for (; i<length; ++i) {
pos=0;
while (i<length) {
if (pattern[pos]==text[i]) {
if (pos==pattern_length-1) {
++count;
break;
}
++pos;++i;
}else{
if (pos>0) {
pos = table[pos-1];
}else
{
pos=0;
}
++i;
}
}
}
return count;
}
int * KmpNext(char * pattern)
{
unsigned long length = strlen(pattern);
int *table = (int *)malloc(sizeof(int) * length),i,pos=0;
for (i=0; i<length; ++i) {
table[i] = 0;
}
i=1;
while (i<length) {
if (pattern[i] == pattern[pos]) {
++pos;
table[i]=pos;
++i;
}else{
if (pos>0) {
--pos;
}else{
table[i]=pos;
++i;
}
}
}
return table;
}