P3375 【模板】KMP字符串匹配

 题目： 模板题。 （ https://www.luogu.org/problemnew/show/P3375 ）

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#define LL long long
#define ULL unsigned long long
#define rep(i,j,k) for(int i=j;i<=k;i++)
#define dep(i,j,k) for(int i=k;i>=j;i--)
#define INF 0x3f3f3f3f
#define mem(i,j) memset(i,j,sizeof(i))
#define make(i,j) make_pair(i,j)
#define pb push_back
using namespace std;
const int N = 1e6 + 5;
int pre[N];
string a, b;
int main() {
    cin >> a >> b;
    int j = -1;
    pre[0] = pre[1] = -1;
    rep(i, 1, (int)b.size() - 1) {
        while( j > -1 && b[i] != b[j + 1]) j = pre[j];
        if(b[j + 1] == b[i]) j++;
        pre[i] = j;
    }
    rep(i, 0, (int)a.size() - 1) {
        while( j != -1 && b[j + 1] != a[i]) j = pre[j];
        if(a[i] == b[j + 1]) j++;
        if( j == (int)b.size() - 1) {
            cout << i - b.size() + 2 <<endl;
            j = pre[j];
        }
    }
    rep(i, 0, (int)b.size() - 1) {
        cout << pre[i] + 1 << " ";
    }
    return 0;
}