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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. struct TreeNode{
  4. 	TreeNode* left;
  5. 	TreeNode*right;
  6. 	int val;
  7. 	TreeNode(int val):left(nullptr),right(nullptr),val(val){};
  8. };
  9. void helper(TreeNode* root,vector<int>&in){
  10. 	if(root == nullptr)return;
  11.  
  12. 	helper(root->left,in);
  13. 	in.push_back(root->val);
  14. 	helper(root->right,in);
  15.  
  16. }
  17. vector<int>inOrd(TreeNode* root){
  18. 	 vector<int>in;
  19. 	 helper(root,in);
  20. 	 return in;
  21. }
  22. TreeNode* buildTree(){
  23. 	int x;
  24. 	cin>>x;
  25. 	if(x==-1)return nullptr;
  26. 	TreeNode* root = new TreeNode(x);
  27.  
  28. 	queue<TreeNode*>q;
  29. 	q.push(root);
  30. 	while(!q.empty()){
  31. 		auto u = q.front();
  32. 		q.pop();
  33.  
  34. 		if(cin>>x && x!=-1){
  35. 			u->left = new TreeNode(x);
  36. 			q.push(u->left);
  37. 		}
  38.  
  39. 		if(cin>>x && x!=-1){
  40. 			u->right = new TreeNode(x);
  41. 			q.push(u->right);
  42. 		}
  43. 	}
  44. 	return root;
  45. }
  46. int main() {
  47.     TreeNode* root = buildTree();
  48.     vector<int>ans = inOrd(root);
  49.     for(int x : ans)cout<<x<<endl;
  50. 	return 0;
  51. }
Success #stdin #stdout 0.01s 5316KB
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https://ideone.com/9pATYJ
language:
C++14 (gcc 8.3)
created:
21 hours ago
visibility:
public

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