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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. struct TreeNode{
  4. 	int val;
  5. 	TreeNode*left;
  6. 	TreeNode*right;
  7. 	TreeNode(int val):left(nullptr),right(nullptr),val(val){};
  8. };
  9. int dfs(TreeNode* root){
  10. 	if(root == nullptr)return 0;
  11. 	int left = dfs(root->left);
  12. 	if(left == -1)return -1;
  13. 	int right = dfs(root->right);
  14. 	if(right == -1)return -1;
  15. 	if(abs(left-right)>1)return -1;
  16. 	return 1+max(left,right);
  17. }
  18. bool balanced(TreeNode* root){
  19. 	return dfs(root)!=-1;
  20. }
  21.  
  22. TreeNode* buildTree(){
  23. 	int x;cin>>x;
  24. 	if(x==-1)return nullptr;
  25. 	TreeNode* root = new TreeNode(x);
  26. 	queue<TreeNode*>q;
  27. 	q.push(root);
  28.  
  29. 	while(!q.empty()){
  30. 		auto u = q.front();
  31. 		q.pop();
  32.  
  33. 		if(cin>>x && x!=-1){
  34. 			u->left = new TreeNode(x);
  35. 			q.push(u->left);
  36. 		}
  37.  
  38. 		if(cin>>x && x!=-1){
  39. 			u->right = new TreeNode(x);
  40. 			q.push(u->right);
  41. 		}
  42. 	}
  43. 	return root;
  44. }
  45. int main() {
  46.     TreeNode*root = buildTree();
  47.   cout << (balanced(root) ? "true" : "false") << "\n";
  48. 	return 0;
  49. }
Success #stdin #stdout 0.01s 5320KB
comments (?)
stdin
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3 9 20 -1 -1 15 7
stdout
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true
https://ideone.com/3GW1Y9
language:
C++14 (gcc 8.3)
created:
2 days ago
visibility:
public

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