|
| 1 | +""" |
| 2 | +Given a binary tree root and an integer target, delete all the leaf nodes with value target. |
| 3 | + |
| 4 | +Note that once you delete a leaf node with value target, if its parent node becomes a leaf node and has the value target, it should also be deleted (you need to continue doing that until you cannot). |
| 5 | + |
| 6 | + |
| 7 | + |
| 8 | +Example 1: |
| 9 | + |
| 10 | + |
| 11 | + |
| 12 | +Input: root = [1,2,3,2,null,2,4], target = 2 |
| 13 | +Output: [1,null,3,null,4] |
| 14 | +Explanation: Leaf nodes in green with value (target = 2) are removed (Picture in left). |
| 15 | +After removing, new nodes become leaf nodes with value (target = 2) (Picture in center). |
| 16 | +Example 2: |
| 17 | + |
| 18 | + |
| 19 | + |
| 20 | +Input: root = [1,3,3,3,2], target = 3 |
| 21 | +Output: [1,3,null,null,2] |
| 22 | +Example 3: |
| 23 | + |
| 24 | + |
| 25 | + |
| 26 | +Input: root = [1,2,null,2,null,2], target = 2 |
| 27 | +Output: [1] |
| 28 | +Explanation: Leaf nodes in green with value (target = 2) are removed at each step. |
| 29 | + |
| 30 | + |
| 31 | +Constraints: |
| 32 | + |
| 33 | +The number of nodes in the tree is in the range [1, 3000]. |
| 34 | +1 <= Node.val, target <= 1000 |
| 35 | +""" |
| 36 | + |
| 37 | + |
| 38 | +# Definition for a binary tree node. |
| 39 | +# class TreeNode: |
| 40 | +# def __init__(self, val=0, left=None, right=None): |
| 41 | +# self.val = val |
| 42 | +# self.left = left |
| 43 | +# self.right = right |
| 44 | +class Solution: |
| 45 | + def removeLeafNodes(self, root: Optional[TreeNode], target: int) -> Optional[TreeNode]: |
| 46 | + if root.left: root.left = self.removeLeafNodes(root.left, target) |
| 47 | + if root.right: root.right = self.removeLeafNodes(root.right, target) |
| 48 | + return None if not root.left and not root.right and root.val == target else root |
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