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| void nex(char *s, int *next)
{
next[0] = 0;
int now = 0, x = 1;
while (x < strlen(s))
{
if (s[now] == s[x])
{
now += 1;
next[x] = now;
x += 1;
}
else if (now)
{
now = next[now - 1];
}
else
{
next[x] = 0;
x += 1;
}
}
}
int kmp(char *s, char *p)
{
int *next = NULL;
next = (int *)malloc(sizeof(int) * strlen(p));
nex(p, next);
int now = 0, px = 0;
while (now < strlen(s))
{
if (p[px] == s[now])
{
px += 1;
now += 1;
}
else if (px)
px = next[px - 1];
else
now += 1;
if (px == strlen(p))
{
return now-px;
}
}
return -1;
}
int strStr(char * haystack, char * needle){
if(!strlen(needle))
return 0;
return kmp(haystack,needle);
}
|