LightOJ 1255 Substring Frequency (KMP模板)

http://lightoj.com/volume_showproblem.php?problem=1255

/*0.068s,7548KB*/

#include<bits/stdc++.h>
using namespace std;
const int mx = 1000005;

char t[mx], p[mx];
int f[mx];

void getfail()
{
	f[0] = f[1] = 0;
	for (int i = 1; p[i]; ++i)
	{
		int j = f[i];
		while (j && p[i] != p[j]) j = f[j];
		f[i + 1] = (p[i] == p[j] ? j + 1 : 0);
	}
}

int find()
{
	int m = strlen(p), cnt = 0;
	getfail();
	int j = 0;
	for (int i = 0; t[i]; ++i)
	{
		while (j && p[j] != t[i]) j = f[j];
		if (p[j] == t[i]) ++j;
		if (j == m) ++cnt;
	}
	return cnt;
}

int main()
{
	int tt;
	scanf("%d", &tt);
	getchar();
	for (int cas = 1; cas <= tt; ++cas)
	{
		gets(t), gets(p);
		printf("Case %d: %d\n", cas, find());
	}
	return 0;
}