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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. void executeTime() {
  5.     cerr << "Time Taken: " << (float)clock() / CLOCKS_PER_SEC << " secs";
  6. }
  7.  
  8. int main() {
  9.  
  10.     int n; cin >> n;
  11.  
  12.     vector<vector<int>> mp(n + 1);
  13.  
  14.     for (int i = 0; i < n - 1; i++) {
  15.         int u, v; cin >> u >> v;
  16.  
  17.         mp[u].push_back(v);
  18.         mp[v].push_back(u);
  19.     }
  20.  
  21.  
  22.     function<int(int, int)> solve = [&](int src, int p) {
  23.  
  24.         int cnt = 0;
  25.  
  26.         for (auto &v : mp[src]) {
  27.             if (v == p) {
  28.                 cnt++;
  29.                 continue;
  30.             };
  31.  
  32.             int ans = solve(v, src);
  33.             if (ans != -1) return ans;
  34.  
  35.             cnt += 1;
  36.         }
  37.  
  38.         if (cnt < 3) return src;
  39.  
  40.         return -1;
  41.     };
  42.  
  43.     int ans = solve(1, -1);
  44.  
  45.     cout << ans << endl;
  46.  
  47.     executeTime();
  48.     return 0;
  49. }
Success #stdin #stdout #stderr 0s 5320KB
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stdout
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stderr
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Time Taken: 0.004281 secs
https://ideone.com/efeXEu
language:
C++14 (gcc 8.3)
created:
6 hours ago
visibility:
public

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