Submission #1039071

#	Time	Username	Problem	Language	Result	Execution time	Memory
1039071		biserailieva	Network (BOI15_net)	C++14	0 / 100	1 ms	2904 KiB

net

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

using ll = long long;

const int MOD = 1e9 + 7;
const int N = 1e5 + 11;

int n;
vector<int> adj[N], leaf;

void sol() {
    cin >> n;
    for (int i = 1; i < n; i++) {
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    for (int i = 1; i <= n; i++) {
        if (adj[i].size() == 1) {
            leaf.push_back(i);
        }
    }
    int sz = leaf.size();
    cout << (sz + 1) / 2 << '\n';
    for (int i = 0; i + 1 < sz; i += 2) {
        cout << leaf[i] << ' ' << leaf[i + 1] << '\n';
    }
    if (sz % 2 == 1) {
        cout << leaf[sz - 1] << ' ' << 1 << '\n';
    }
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int t = 1;
    //cin >> t;
    while (t--) {
        sol();
    }
}

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