题目：
题解：
class Solution:# 在【100. 相同的树】的基础上稍加改动def isSameTree(self, p: Optional[TreeNode], q: Optional[TreeNode]) -> bool:if p is None or q is None:return p is qreturn p.val == q.val and self.isSameTree(p.left, q.right) and self.isSameTree(p.right, q.left)def isSymmetric(self, root: Optional[TreeNode]) -> bool:return self.isSameTree(root.left, root.right)
