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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. struct TreeNode{
  4. 	int val;
  5. 	TreeNode*right;
  6. 	TreeNode*left;
  7. 	TreeNode(int val):left(nullptr),right(nullptr),val(val){};
  8. };
  9. int height(TreeNode* root){
  10. 	if(root == nullptr)return 0;
  11. 	return 1+ max(height(root->right),height(root->left));
  12. }
  13. int diameter(TreeNode*root){
  14. 	if(root == nullptr)return 0;
  15.  
  16. 	int l = height(root->left);
  17. 	int r = height(root->right);
  18.  
  19. 	int ld = diameter(root->left);
  20. 	int rd = diameter(root->right);
  21.  
  22. 	return max(l+r,max(ld,rd));
  23. }
  24. TreeNode* buildTree(){
  25. 	int x;cin>>x;
  26. 	if(x==-1)return nullptr;
  27. 	TreeNode* root = new TreeNode(x);
  28.  
  29. 	queue<TreeNode*>q;
  30. 	q.push(root);
  31.  
  32. 	while(!q.empty()){
  33. 		auto u = q.front();
  34. 		q.pop();
  35.  
  36. 		if(cin>>x && x!=-1){
  37. 			u->left = new TreeNode(x);
  38. 			q.push(u->left);
  39. 		}
  40. 			if(cin>>x && x!=-1){
  41. 			u->right = new TreeNode(x);
  42. 			q.push(u->right);
  43. 		}
  44. 	}
  45. 	return root;
  46. }
  47. int main() {
  48.     TreeNode* root = buildTree();
  49.     cout<<diameter(root);
  50. 	return 0;
  51. }
Success #stdin #stdout 0.01s 5284KB
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https://ideone.com/v09fyB
language:
C++14 (gcc 8.3)
created:
2 days ago
visibility:
public

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