226. Invert Binary Tree

https://leetcode.com/problems/invert-binary-tree/

solution

class Solution:
    def invertTree(self, root: Optional[TreeNode]) -> Optional[TreeNode]:
        if root is None:
            return None

        root.left, root.right = root.right, root.left
        self.invertTree(root.left)
        self.invertTree(root.right)
        return root

时间复杂度：O(n) 空间复杂度：O(h)