hdu 1686(kmp)

题意：两个字符串，模式串和目标串，输出每个模式串在目标串中出现次数，可重叠。

题解：kmp模板题，每次找到后数量加一。

#include <stdio.h> 
#include <string.h>
const int N = 1000005;

char p[N], t[N];
int next[N], len1, len2;

void getnext() {
	int pp = -1, k = 0;
	next[0] = -1;
	while (k < len2) {
		if (pp == -1 || p[pp] == p[k]) {
			k++;
			pp++;
			next[k] = pp;
		}
		else
			pp = next[pp];
	}
}

int kmp() {
	int pp = 0, tt = 0, count = 0;
	while (tt < len1) {
		if (pp == -1 || t[tt] == p[pp]) {
			pp++;
			tt++;
		}
		else
			pp = next[pp];
		if (pp == len2)
			count++;
	}
	return count;
}

int main() {
	int cases;
	scanf("%d", &cases);
	while (cases--) {
		scanf("%s", p);
		scanf("%s", t);
		len1 = strlen(t);
		len2 = strlen(p);
		getnext();
		int ans = kmp();
		printf("%d\n", ans);
	}
	return 0;
}