翻转二叉树 （Python）

​​LeetCode链接​​

其实就是遍历二叉树的每个节点 然后交换其 left和right

# 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: TreeNode) -> TreeNode:
        def invert(root: TreeNode):
            if not root:
                return
            root.left, root.right = root.right, root.left
            invert(root.left)
            invert(root.right)
        invert(root)
        return root