fork download
copy 
  1. #include<bits/stdc++.h>
  2. using namespace std;
  3. set<int> ans;
  4. vector< vector<int> > tree(10001);
  5. int mx = 0;
  6. void ldfs(int id, int ht, int p=-1){
  7.     if(ht > mx){
  8.         mx = ht;
  9.         ans.insert(id);
  10.         //cout<<id<<endl;
  11.     }
  12.     for(int i=0; i<tree[id].size(); ++i)
  13.         if(tree[id][i] != p)
  14.             ldfs(tree[id][i], ht+1, id);
  15. }
  16. void rdfs(int id, int ht, int p=-1){
  17.     if(ht > mx){
  18.         mx = ht;
  19.         ans.insert(id);
  20.         //cout<<id<<endl;
  21.     }
  22.     for(int i=tree[id].size()-1; i>=0; --i)
  23.         if(tree[id][i] != p)
  24.             rdfs(tree[id][i], ht+1, id);
  25. }
  26. int main(){
  27.     #ifndef ONLINE_JUDGE
  28.         freopen("inp.txt", "r", stdin);
  29.     #endif // ONLINE_JUDGE
  30.     int test;
  31.     cin>>test;
  32.     while(test--){
  33.         int n;
  34.         int x, y;
  35.         cin >> n;
  36.         assert(n<=100000 and n>=3);
  37.         ans.clear();
  38.         tree.clear();
  39.         tree.resize(n+1);
  40.         for(int i=1; i<=n-1; ++i){
  41.             cin >> x >> y;
  42.             //assert(x<=y and y<=n and x>=1);
  43.             tree[x].push_back(y);
  44.             tree[y].push_back(x);
  45.         }
  46.         /*
  47.         for(int i=1; i<=n; ++i){
  48.             for(auto it: tree[i])
  49.                 cout<<it<<" ";
  50.             cout<<endl;
  51.         }
  52.         */
  53.         mx = 0;
  54.         ldfs(1, 1);
  55.         mx = 0;
  56.         rdfs(1, 1);
  57.         for(auto it: ans)
  58.             cout<<it<<" ";
  59.         cout<<endl;
  60.  
  61.     }
  62.  
  63. }
Runtime error #stdin #stdout #stderr 0s 3420KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
Standard output is empty
stderr
copy 
prog: prog.cpp:36: int main(): Assertion `n<=100000 and n>=3' failed.
https://ideone.com/pY455C
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!