KMP算法

include <stdio.h>

include <stdlib.h>

include <string.h>

// 这个还是有些问题的！！
void
get_next_flaw(char * t, int next[])
{
int i, j;

i = 0; j = -1; next[i] = -1;// 先规定好最初始的next值
while (i < strlen(t))
{
	if (j == -1 || t[i] == t[j]) {// 如果是初始值j==0 ????
		++i; ++j;
		next[i] = j;
	} else {
		j = next[j];
	}
}

}

void
get_next(char * t, int next[])
{
int i, j;

i = 0; j = -1; 
next[i] = j;// 先规定好最初始的next值
while (i <= strlen(t))
{
	if (j == -1 // 初始条件，边界值
		|| t[i] == t[j]) {

		++i; ++j;

		if (t[i] != t[j])
			next[i] = j;
		else
			next[i] = next[j];
	} else {
		j = next[j];
	}
}

}

int
index_kmp(char * s, char * t, int pos)
{
int i, j;
int * next;
int len1, len2;

next = malloc(sizeof(int) * strlen(t));
memset(next, 0, sizeof(int) * strlen(t));

len1 = strlen(s);
len2 = strlen(t);

get_next(t, next);

if 1

i = -1;
while (++i < strlen(t))	{
	printf("%d\t", next[i]);
}

endif

i = pos-1; j = -1;
while (i < len1 && j < len2) {
	if (j == -1 || s[i] == t[j]) {
		++i; ++j;
	} else {
		j = next[j];
	}
}

//free(next);

if (j >= strlen(t))
	return i - strlen(t);
else
	return -1;

}

int main()
{
char s, t;
int pos;
/01234567/
s = "acabaabaabcacaabc";
t = "abaabcac";

pos = index_kmp(s, t, 0);
printf("find at %d\n", pos);

getchar();
return 0;

}