leetcode

0 class Solution {

1 TreeNode *deleteRoot(TreeNode *root) {

2 if (!root) return nullptr;

3 if (!root->left) return root->right;

4 if (!root->right) return root->left;

5

6 TreeNode *next = root->right;

7 TreeNode *pre = nullptr;

8 while (next->left) {

9 pre = next;

10 next = next->left;

11 }

12 next->left = root->left;

13 if (root->right != next) {

14 pre->left = next->right;

15 next->right = root->right;

16 }

17 return next;

18 }

19

20 public:

21 TreeNode *deleteNode(TreeNode *root, int key) {

22 TreeNode *cur = root, *pre = nullptr;

23 while (cur && cur->val != key) {

24 pre = cur;

25 cur = key < cur->val ? cur->left : cur->right;

26 }

27

28 if (!pre) return deleteRoot(cur);

29 (pre->left == cur ? pre->left : pre->right) = deleteRoot(cur);

30 return root;

31 }

32 };