KMP
#include <iostream>
using namespace std;
const int N = 100010, M = 1000010;
int n, m;
char p[N], s[M];
int ne[N]; // next 数组 注意是:当前字符匹配失败,这个字符之前的数组可以怎么移动(next)
int main()
{
cin >> n >> p+1 >> m >> s+1;
for (int i = 2, j = 0; i <= n; i++)
{
while (j && p[i] != p[j+1])
j = ne[j];
if (p[i] == p[j+1])
j++;
ne[i] = j;
}
for (int i = 1, j = 0; i <= m; i++)
{
while (j && s[i] != p[j + 1])
j = ne[j];
if (s[i] == p[j + 1])
j++;
if (j == n)
{
printf(“%d “, i – n);
j = ne[j];
}
}
return 0;
}