leetcode/tree/symmetric_tree.py

from typing import Optional
from tree import TreeNode


class Polution:
    def isSymmetric(self, root: Optional[TreeNode]) -> bool:
        p = root.left
        q = root.right
        while p and q:
            if p.val == q.val:
                p = p.left
                q = q.right
            else:
                return False