So basically, we could do an preorder traversal with 2 trees at the same time to check whether they are equal. And this could be done recursively.
# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class Solution:
def isSameTree(self, p: TreeNode, q: TreeNode) -> bool:
if p is None and q is None:
return True
elif p is None or q is None:
return False
elif p.val != q.val:
return False
if self.isSameTree(p.left, q.left) and self.isSameTree(p.right, q.right):
return True
return False