【HDU1686】Oulipo

KMP模板题

#include<cstdio>
#include<cstring>
using namespace std;
int pre[1000010],m[1000010];
char p[1000010],q[1000010];
int KMP(int l1,int l2){
    int sum=0;
    memset(pre,0,sizeof(pre));
    memset(m,0,sizeof(m));
    pre[1]=0;
    for (int i=2;i<=l1;i++){
        int j=pre[i-1];
        while (j&&p[j+1]!=p[i]) j=pre[j];
        if (p[j+1]==p[i]) j++;
        pre[i]=j;
    }
    m[1]=0;
    for (int i=1;i<=l2;i++){
        int j=m[i-1];
        while (j&&q[i]!=p[j+1]) j=pre[j];
        if (p[j+1]==q[i]) j++;
        m[i]=j;
        if (j==l1){
            j=pre[j];sum++;
        }
    }
    return sum;
}
int main(){
    int Q,lenp,lenq; 
    scanf("%d",&Q);
    while (Q--){
        scanf("%s",p+1);
        lenp=strlen(p+1);
        scanf("%s",q+1);
        lenq=strlen(q+1);
        printf("%d\n",KMP(lenp,lenq));
    }
    return 0;
}