leetcode

0 class Solution {

1 public:

2 TreeNode *removeLeafNodes(TreeNode *root, int target) {

3 TreeNode dummy(-1, root, nullptr);

4 unordered_map<TreeNode *, TreeNode *> um = {{root, &dummy}};

5 stack<TreeNode *> st({root});

6 while (!st.empty()) {

7 TreeNode *root = st.top();

8 if (root->val < 0) {

9 st.pop();

10 root->val = -root->val;

11 if (!root->left && !root->right && root->val == target) {

12 TreeNode *parent = um[root];

13 (parent->left == root ? parent->left : parent->right) = nullptr;

14 }

15 continue;

16 }

17 root->val = -root->val;

18 if (root->left) {

19 um[root->left] = root;

20 st.push(root->left);

21 }

22 if (root->right) {

23 um[root->right] = root;

24 st.push(root->right);

25 }

26 }

27 return dummy.left;

28 }

29 };