leetcode

0 class Solution {

1 public:

2 TreeNode *increasingBST(TreeNode *root) {

3 TreeNode *head, *tmp;

4 tmp = head = new TreeNode();

5 stack<TreeNode *> st;

6 while (true) {

7 while (root) {

8 st.push(root);

9 root = root->left;

10 }

11 if (st.empty()) break;

12 root = st.top();

13 st.pop();

14 tmp = tmp->right = root;

15 tmp->left = nullptr;

16 root = root->right;

17 }

18 return head->right;

19 }

20 };