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 targetif 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 = 2
Output: [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 = 3
Output: [1,3,null,null,2]


Example 3:

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


Example 4:

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


Example 5:

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


Constraints:

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

## Solution: Recursion

Post-order traversal

Time complexity: O(n)
Space complexity: O(n)

## C++

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