leetcode

0 class Solution {

1 public:

2 void flatten(TreeNode *root) {

3 TreeNode *crnt = new TreeNode(-1);

4 stack<TreeNode *> st;

5 st.push(root);

6 while (!st.empty()) {

7 TreeNode *root = st.top();

8 st.pop();

9 crnt->right = root;

10 while (root) {

11 crnt = root;

12 if (root->right) st.push(root->right);

13

14 root->right = root->left;

15 root->left = nullptr;

16 root = root->right;

17 }

18 }

19 }

20 };