HDU-1686 Oulipo

传送门

t组数据 求模式串在文本串中的出现次数（允许重叠）

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
typedef long long LL;

const int maxm = 1e4 + 10;
const int maxn = 1e6 + 10;
char P[maxm], T[maxn];
int f[maxm];

int Tc, N, M;
int ans;

void getFail(char* p, int *f) {
    f[0] = 0;
    f[1] = 0;
    for (int i = 1; i < M; i++) {
        int j = f[i];
        while (j && P[i] != P[j]) j = f[j];
        f[i + 1] = P[i] == P[j] ? j + 1 : 0;
    }
}

void find(char* T, char* P, int* f) {
    int j = 0;
    for (int i = 0; i < N; i++) {
        while (j && P[j] != T[i]) j = f[j];
        if (P[j] == T[i]) j++;
        if (j == M) {
            ans++;
            if (j != 1) {
                i--;
                j--;
                j = f[j];    
            }
            
        }
    }
}

int main() {
    scanf("%d", &Tc);
    while (Tc--) {
        ans = 0;
        scanf("%s", P);
        scanf("%s", T);
        N = strlen(T);
        M = strlen(P);
        getFail(P, f);
        find(T, P, f);
        printf("%d
", ans);
    }

    return 0;
}