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  1. #include<bits/stdc++.h>
  2. using namespace std;
  3.  
  4. #define ll long long
  5. ll cost[1000000];
  6.  
  7. void dfs(int node,vector<int>t[],vector<int>&v,vector<int>&parent,vector<int>&b){
  8.     v[node]=1;
  9.     for(auto it:t[node]){
  10.         if(v[it]==0){
  11.             parent[it]=node;
  12.             dfs(it,t,v,parent,b);
  13.         }
  14.     }
  15.     ll c=0;
  16.     for(auto child:t[node]){
  17.         if(child!=parent[node])c+=cost[child];
  18.     }
  19.     cost[node]=c+b[node];
  20. }
  21.  
  22. int main(){
  23.     ios_base::sync_with_stdio(false);
  24.     cin.tie(NULL);
  25.     int n;
  26.     cin>>n;
  27.     vector<int>t[n+1];
  28.     vector<int>v(n+1),parent(n+1),b(n+1);
  29.     for(int i=1;i<=n;i++)cin>>b[i];
  30.     for(int i=1;i<n;i++){
  31.         int x,y;
  32.         cin>>x>>y;
  33.         t[x].push_back(y);
  34.         t[y].push_back(x);
  35.     }
  36.     dfs(1,t,v,parent,b);
  37.     ll ans=0;
  38.     for(int i=1;i<=n;i++){
  39.         ans=max(ans,cost[i]);
  40.     }
  41.     cout<<"Max subtree sum is "<<ans<<"\n";
  42.     return 0;
  43. }
Success #stdin #stdout 0.01s 5288KB
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Max subtree sum is 21
https://ideone.com/NP8Fol
language:
C++14 (gcc 8.3)
created:
7 days ago
visibility:
public

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