LeetCode-1325. Delete Leaves With a Given Value

LeetCode-1325. Delete Leaves With a Given Value

Given a binary tree ​​root​​​ and an integer ​​target​​, delete all the leaf nodes with value ​​target​​.

Note that once you delete a leaf node with value ​​target​​, if it's parent node becomes a leaf node and has the value ​​target​​, it should also be deleted (you need to continue doing that until you can't).

Example 1:

Input: root = [1,2,3,2,null,2,4], target = 2Output: [1,null,3,null,4]Explanation: Leaf nodes in green with value (target = 2) are removed (Picture in left). After removing, new nodes become leaf nodes with value (target = 2) (Picture in center).

Example 2:

Input: root = [1,3,3,3,2], target = 3Output: [1,3,null,null,2]

Example 3:

Input: root = [1,2,null,2,null,2], target = 2Output: [1]Explanation: Leaf nodes in green with value (target = 2) are removed at each step.

Example 4:

Input: root = [1,1,1], target = 1Output: []

Example 5:

Input: root = [1,2,3], target = 1Output: [1,2,3]

Constraints:

​​1 <= target <= 1000​​Each tree has at most​​3000​​ nodes.Each node's value is between​​[1, 1000]​​.

题解：

后序遍历。

class Solution {public: void Delete(TreeNode* &root, int target) { if (root != NULL) { Delete(root->left, target); Delete(root->right, target); if (root->left == NULL && root->right == NULL && root->val == target) { root = NULL; } } } TreeNode* removeLeafNodes(TreeNode* root, int target) { Delete(root, target); return root; }};

版权声明：本文内容由网络用户投稿，版权归原作者所有，本站不拥有其著作权，亦不承担相应法律责任。如果您发现本站中有涉嫌抄袭或描述失实的内容，请联系我们jiasou666@gmail.com 处理，核实后本网站将在24小时内删除侵权内容。