Submission #1307964

#	Time	Username	Problem	Language	Result	Execution time	Memory
1307964		ballbreaker	Network (BOI15_net)	C++20	0 / 100	1 ms	14624 KiB

net

#include<bits/stdc++.h>
#pragma GCC optimize("Ofast,unroll-loops")
using namespace std;
main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    int cnt[n + 1] = {};
    for (int i = 1; i < n; i++) {
        int a, b;
        cin >> a >> b;
        cnt[a]++;
        cnt[b]++;
    }
    vector<int>v;
    for (int i = 1; i <= n; i++) {
        if (cnt[i] == 1) {
            v.push_back(i);
        }
    }
    if (v.size() & 1) {
        for (int i = 1; i <= n; i++) {
            if (cnt[i] > 1) {
                v.push_back(i);
                break;
            }
        }
    }
    cout << v.size() / 2 << '\n';
    for (int i = 0; i < v.size(); i += 2) {
        cout << v[i] << ' ' << v[i + 1] << endl;
    }
}

Compilation message (stderr)

net.cpp:4:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
    4 | main() {
      | ^~~~

• Subtask 1: 0 / 18
• Subtask 2: 0 / 45
• Subtask 3: 0 / 37