Submission #1131193

#	Time	Username	Problem	Language	Result	Execution time	Memory
1131193		pera	Network (BOI15_net)	C++20	0 / 100	0 ms	324 KiB

net

#include<bits/stdc++.h>
using namespace std;
int main(){
   int n;
   cin >> n;
   vector<vector<int>> g(n + 1);
   for(int i = 1;i < n;i ++){
      int u , v;
      cin >> u >> v;
      g[u].emplace_back(v);
      g[v].emplace_back(u);
   }
   vector<int> e;
   for(int i = 1;i <= n;i ++){
      if((int)g[i].size() == 1){
         e.emplace_back(i);
      }
   }
   cout << ((int)e.size() + 1) / 2 << '\n';
   int l = 0 , r = (int)e.size() - 1;
   while(l < r){
      cout << e[l++] << " " << e[r--] << '\n'; 
   }
   if(l == r){
      cout << e[0] << " " << e[l] << '\n';
   }
}

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