Submission #137064

#	Time	Username	Problem	Language	Result	Execution time	Memory
137064		silxikys	Network (BOI15_net)	C++14	0 / 100	15 ms	12156 KiB

net

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

const int maxn = 5e5+5;
int n;
vector<int> adj[maxn];
int deg[maxn];

int main()
{
    ios_base::sync_with_stdio(false); cin.tie(NULL);
    cin >> n;
    for (int i = 0; i < n - 1; i++) {
        int a, b; cin >> a >> b;
        ++deg[a];
        ++deg[b];
    }
    vector<int> leafs;
    for (int i = 1; i <= n; i++) {
        if (deg[i] == 1) leafs.push_back(i);
    }
    vector<pair<int,int>> ans;
    for (int i = 0; i < leafs.size(); i += 2) {
        ans.push_back({leafs[i],leafs[(i+1)%leafs.size()]});
    }
    //output
    cout << ans.size() << '\n';
    for (auto p: ans) {
        cout << p.first << ' ' << p.second << '\n';
    }
}

Compilation message (stderr)

net.cpp: In function 'int main()':
net.cpp:24:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < leafs.size(); i += 2) {
                     ~~^~~~~~~~~~~~~~

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