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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. //function to calculate the points collected in the path
  5. int dfs(int x, vector<vector<int>> &arr, vector<bool> &vis, vector<int> &weight){
  6. 	int points_max = 0 ; 
  7. 	int points = 0 ; 
  8. 	vis[x] = true ;
  9.  
  10. 	for(auto &i: arr[x]){
  11. 		if(!vis[i]){
  12. 			points = dfs(i, arr, vis, weight) ;
  13. 		}
  14. 		points_max = max(points_max, points) ; 
  15. 	}
  16.  
  17. 	return weight[x] + points_max ; 
  18. }
  19.  
  20. int main() {
  21.  
  22. 	// input starts
  23.  
  24. 	int N ; 
  25. 	cin >> N ; 
  26.  
  27. 	vector<vector<int>> arr(N + 1) ;
  28.  
  29. 	vector<bool> vis(N + 1, false) ;
  30.  
  31. 	vector<int> weight(N + 1) ; 
  32.  
  33. 	vector<int> ans ; 
  34.  
  35. 	for(int i = 1; i <= N; ++i)cin >> weight[i] ;
  36.  
  37. 	int u, v;
  38.  
  39. 	for(int i = 0; i < N - 1; ++i){
  40. 		cin >> u >> v ;
  41. 		arr[u].push_back(v) ;
  42. 		arr[v].push_back(u) ;
  43. 	}
  44.  
  45. 	// input ends here
  46.  
  47. 	vis[1] = true ;
  48.  
  49. 	for(auto &x: arr[1]){
  50. 		ans.push_back(dfs(x, arr, vis, weight)) ;
  51. 	}
  52.  
  53. 	sort(ans.begin(), ans.end(), greater<int>()) ; 
  54.  
  55.  
  56. 	// if only 1 node & 0 edges
  57. 	if(ans.size() == 0){
  58. 		cout << weight[1] ; 
  59. 	}
  60. 	// if only 2 node nodes & 1 edge
  61. 	else if(ans.size() == 1){
  62. 		cout << weight[1] + ans[0] ; 
  63. 	}
  64. 	else{
  65. 		cout << ans[0] + ans[1] + weight[1] ;
  66. 	}
  67.  
  68. 	return 0;
  69. }
Success #stdin #stdout 0.01s 5544KB
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https://ideone.com/SJXIlw
language:
C++14 (gcc 8.3)
created:
1 year ago
visibility:
secret

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