Submission #311448

#	Time	Username	Problem	Language	Result	Execution time	Memory
311448		vipghn2003	Network (BOI15_net)	C++14	0 / 100	10 ms	12032 KiB

net

#include<bits/stdc++.h>

using namespace std;

const int N=5e5+5;
int n;
vector<int>leaf;
vector<int>adj[N];

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    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);
    cout<<(leaf.size()+1)/2<<'\n';
    for(int i=0;i+1<leaf.size();i+=2) cout<<leaf[i]<<' '<<leaf[i+1]<<'\n';
    if(leaf.size()%2) cout<<leaf.back()<<' '<<leaf[0]<<'\n';
}

Compilation message (stderr)

net.cpp: In function 'int main()':
net.cpp:24:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   24 |     for(int i=0;i+1<leaf.size();i+=2) cout<<leaf[i]<<' '<<leaf[i+1]<<'\n';
      |                 ~~~^~~~~~~~~~~~

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