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  1. #include <bits/stdc++.h>
  2.  
  3. using namespace std;
  4.  
  5. // // Common file
  6. // #include <ext/pb_ds/assoc_container.hpp>
  7. // // Including tree_order_statistics_node_update
  8. // #include <ext/pb_ds/tree_policy.hpp>
  9.  
  10. // using namespace __gnu_pbds;
  11. // #define ordered_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
  12. //asd
  13.  
  14. #define MOD 1000000007
  15.  
  16. void fast() {
  17.     cin.sync_with_stdio(false);
  18.     cout.sync_with_stdio(false);
  19.     cin.tie(0);
  20.     cout.tie(0);
  21. }
  22.  
  23. vector <vector<int>> graph;
  24.  
  25. int infect = 0, spread = 0;
  26.  
  27. void dfs(int i) {
  28.  
  29.  
  30.     infect += min((int)graph[i].size(), 1);
  31.     spread += max((int)graph[i].size() - 1, 0);
  32.  
  33.     //cout << i << " " << min((int)graph[i].size(), 1) << " " << max((int)graph[i].size() - 1, 0)  << "\n";
  34.  
  35.     for(auto j: graph[i])
  36.         dfs(j);
  37. }
  38.  
  39. int main() {
  40.     //fast();
  41.     //freopen("input.in", "r", stdin);
  42.     //freopen("output.out", "w", stdout);
  43.     int t;
  44.     t = 1;
  45.     cin >> t;
  46.  
  47. 	while(t--) {
  48.         //cout << "hi\n";
  49.         int n;
  50.         cin >> n;
  51.  
  52.         graph.assign(n+1, {});
  53.         infect = 1;
  54.         spread = 0;
  55.  
  56.         for(int i = 2; i <= n; i ++) {
  57.             int a;
  58.             cin >> a;
  59.             graph[a].push_back(i);
  60.         }
  61.  
  62.         dfs(1);
  63.  
  64.         if(infect > spread) {
  65.             cout << infect << "\n";
  66.         } else {
  67.             cout << (long long)(1 + ceil((spread + infect - 1) / 2.0)) << "\n";
  68.         }
  69.     }
  70. }
Success #stdin #stdout 0.01s 5504KB
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https://ideone.com/PW6Lsd
language:
C++ (gcc 8.3)
created:
2 years ago
visibility:
secret

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