KMP 模板

AcWing 831. KMP字符串

#include <iostream>
#include <string>

using namespace std;

const int N = 1E5 + 10, M = 1E6 + 10;
int n, m;
char p[N], s[M];
int ne[N];

int main() {
    cin >> n >> p + 1 >> m >> s + 1;
    
    //自己匹配自己的一个过程
    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) {
            cout << i - n << " ";
            j = ne[j];
        }
    }
    
    return 0;
}