【树】面试题 17.12. BiNode

 1 /**
 2  * Definition for a binary tree node.
 3  * struct TreeNode {
 4  *     int val;
 5  *     TreeNode *left;
 6  *     TreeNode *right;
 7  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 8  * };
 9  */
10 class Solution {
11 public:
12     TreeNode *ans = new TreeNode(0);
13     TreeNode *cur=ans;
14 
15     void inOrder(TreeNode* node)
16     {
17         if(node==NULL)  
18         {
19             return ;
20         }
21 
22         inOrder(node->left);
23         node->left=NULL;    //将该节点的左孩子设为NULL
24         cur->right=node;    //将该节点赋给上一个节点的右孩子
25         cur=node;           //更新cur
26         inOrder(node->right);
27     }
28     TreeNode* convertBiNode(TreeNode* root) 
29     {
30         inOrder(root);
31         return ans->right;
32     }
33 };