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  1. #include<bits/stdc++.h>
  2. using namespace std;
  3.  
  4. const long long MaxN = 1e6;
  5.  
  6. long long n,k,res;
  7. vector<long long> a[MaxN+5];
  8. bool visited[MaxN+5];
  9. long long depth[MaxN+5];
  10.  
  11. void input()
  12. {
  13.     cin >> n >> k;
  14.  
  15.     for(long long i=1;i<=n-1;i++)
  16.     {
  17.         long long u,v;
  18.         cin >> u >> v;
  19.         a[u].push_back(v);
  20.         a[v].push_back(u);
  21.     }
  22. }
  23.  
  24. void dfs(long long i)
  25. {
  26.     stack<long long> st;
  27.     st.push(i);
  28.     visited[i]=true;
  29.  
  30.     while(!st.empty())
  31.     {
  32.         long long u=st.top();
  33.         st.pop();
  34.  
  35.         for(long long v:a[u])
  36.         {
  37.             if(!visited[v])
  38.             {
  39.                 visited[v]=true;
  40.                 depth[v]=depth[u]+1;
  41.                 st.push(v);
  42.             }
  43.         }
  44.     }
  45. }
  46.  
  47. void solve()
  48. {
  49.     for(long long i=1;i<=n;i++)
  50.     {
  51.         visited[i]=false;
  52.         depth[i]=0;
  53.     }
  54.  
  55.     dfs(1);
  56.  
  57.     sort(depth+1,depth+n+1,greater<long long>());
  58.  
  59.     res=0;
  60.  
  61.     for(long long i=1;i<=k;i++)
  62.     {
  63.         res+=depth[i];
  64.     }
  65.  
  66.     cout << res;
  67. }
  68.  
  69. int main()
  70. {
  71.     ios_base::sync_with_stdio(0);
  72.     cin.tie(0);
  73.  
  74.     input();
  75.     solve();
  76. }
Success #stdin #stdout 0.01s 29436KB
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https://ideone.com/peLSYp
language:
C++14 (gcc 8.3)
created:
13 hours ago
visibility:
public

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