Pku2752 Seek the Name, Seek the Fame

#include <cstdio>
#include <cstring>
typedef unsigned long long ll;
#define fg(i, j, k, l) for (int i = j; i <= k; i += l)
const int M = 400010;
const ll b = 11;
char c[M];
int len;
ll hh[M] = { 0, b }, a[M];
int main() {
    fg(i, 2, 400010, 1) hh[i] = hh[i - 1] * b;
    while (scanf("%s", c + 1) != EOF) {
        memset(a, 0, sizeof a);
        len = strlen(c + 1);
        fg(i, 1, len, 1) a[i] = a[i - 1] * b + (ll)(c[i]);
        fg(i, 1, len, 1) //暴力枚举，hash出来的前缀是否等于后缀
   
               if (a[i] == a[len] - a[len - i] * hh[i]) printf("%d ", i);
        printf("
");
    }
    return 0;
}

　也可以KMP算法实现

#include<cstdio>
#include<iostream>
#include<cmath>
#include<cstring>
#define maxn 1000010
using namespace std;
char s[maxn];
int n,pre[maxn],list[maxn];
int main(){
    scanf("%d",&n);
    scanf("%s",s+1);
    for (int i=2,j=0;i<=n;i++){
        while (j&&s[j+1]!=s[i]) j=pre[j];
        if (s[j+1]==s[i]) j++;
        pre[i]=j;   
    }
    for (int i=n;i;i=pre[i]) 
           list[++list[0]]=i;
    for (int i=list[0];i>=1;i--) printf("%d ",list[i]);
    printf("
");
    return 0;   
}