HDU1686 Oulipo

题目链接

题解

KMP模板题…

#include <bits/stdc++.h>
using namespace std;
void build_fail(char *pat, int len, int *fail){
    fail[0] = -1;
    for(int i = 1, j = -1; i < len; ++i){
        while(j > -1 && pat[i] != pat[j + 1])
            j = fail[j];
        if(pat[i] == pat[j + 1])
            fail[i] = ++j;
        else
            fail[i] = -1;
    }
}
int KMP_match(char *text, int l1, char *pat, int l2, int *fail){
    int cnt = 0;
    for(int i = 0, j = -1; i < l1; ++i){
        while(j > -1 && text[i] != pat[j + 1])
            j = fail[j];
        if(text[i] == pat[j + 1])
            j++;
        if(j == l2 - 1)
            j = fail[j], cnt++;
    }
    return cnt;
}
int n, m, fail[10005] = {0};
char a[10005], b[1000005];
int main(){
    int T;
    scanf("%d", &T);
    while(T--){
        scanf("%s%s", a, b);
        m = strlen(a), n = strlen(b);
        build_fail(a, m, fail);
        printf("%d\n", KMP_match(b, n, a, m, fail));
    }
    return 0;
}