'''
시간 복잡도: O(n)
공간 복잡도: O(n)
'''
from typing import Optional

# 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 isSameTree(self, p: Optional[TreeNode], q: Optional[TreeNode]) -> bool:
        if not p and not q:
            return True
        if not p or not q:
            return False
        
        return p.val == q.val and self.isSameTree(p.left, q.left) and self.isSameTree(p.right, q.right)
