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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. vector<vector<int>>spiral(TreeNode* root){
  10. 	vector<vector<int>>ans;
  11. 	if(root == nullptr)return ans;
  12.  
  13. 	queue<TreeNode*>q;
  14. 	q.push(root);
  15. 	bool trn = false;
  16. 	while(!q.empty()){
  17. 		int sz = q.size();
  18. 		vector<int>lvl;
  19. 		for(int i = 0;i<sz;i++){
  20. 			auto u = q.front();
  21. 			q.pop();
  22. 			lvl.push_back(u->val);
  23. 			if(u->left){
  24. 				q.push(u->left);
  25. 			}
  26.  
  27. 			if(u->right){
  28. 				q.push(u->right);
  29. 			}
  30. 		}
  31. 		if(trn)reverse(lvl.begin(),lvl.end());
  32. 		ans.push_back(lvl);
  33. 		trn = !trn;
  34. 	}
  35. 	return ans;
  36. }
  37. TreeNode* buildTree(){
  38. 	int x;cin>>x;
  39. 	if(x == -1)return nullptr;
  40. 	TreeNode* root = new TreeNode(x);
  41.  
  42. 	queue<TreeNode*>q;
  43. 	q.push(root);
  44.  
  45. 	while(!q.empty()){
  46. 		auto u = q.front();
  47. 		q.pop();
  48.  
  49. 		if(cin>>x && x!=-1){
  50. 			u->left=new TreeNode(x);
  51. 			q.push(u->left);
  52. 		}
  53.  
  54. 			if(cin>>x && x!=-1){
  55. 			u->right=new TreeNode(x);
  56. 			q.push(u->right);
  57. 		}
  58. 	}
  59. 	return root;
  60. }
  61. int main() {
  62. 	TreeNode* root = buildTree();
  63. 	vector<vector<int>>ans = spiral(root);
  64. 	for(auto &x : ans){
  65. 		for(auto &y:x){
  66. 			cout<<y<<" ";
  67. 		}
  68. 		cout<<endl;
  69. 	}
  70. 	return 0;
  71. }
Success #stdin #stdout 0s 5320KB
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https://ideone.com/maltwN
language:
C++14 (gcc 8.3)
created:
1 day ago
visibility:
public

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