Invert/Flip Binary Tree

Invert a binary tree. Tags: Tree

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Solution

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def invertTree(self, root: Optional[TreeNode]) -> Optional[TreeNode]:
        if not root:
            return
        tmp_left = self.invertTree(root.right)
        tmp_right = self.invertTree(root.left)
        root.left = tmp_left
        root.right = tmp_right
        return root