LeetCode题解(Offer28)：判断二叉树是否左右对称(Python)

题目：​​原题链接​​（简单）

标签：树、二叉树、深度优先搜索

解法一：

class Solution:
    def isSymmetric(self, root: TreeNode) -> bool:
        def dfs(node1, node2):
            if node1 and node2:
                return node1.val == node2.val and dfs(node1.right, node2.left) and dfs(node1.left, node2.right)
            elif node1 or node2:
                return False
            else:
                return True

        return dfs(root.left, root.right) if root else True