Submission

Status:

PPPPPPPPPP

Score: 100

User: Winzzwz

Problemset: ส่งต่อ

Language: cpp

Time: 0.002 second

Submitted On: 2025-03-09 12:25:41

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int n,s,t[1010],mark[1010],cnt = 1;
queue <int> qu;

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin >> n >> s;
    for (int i = 1; i <= n; i++) {
        cin >> t[i];
    }
    qu.push(s);
    while (!qu.empty()) {
        int top = qu.front(); qu.pop();
        if (t[top] && mark[t[top]] == 0) {
            mark[t[top]] = 1;
            qu.push(t[top]);
            cnt++;
        }
    }
    cout << cnt;
    return 0;
}