chal_100.py

class TreeNode(object):
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right


class Solution(object):
    def is_same_tree(self, p, q):
        """
        :type p: TreeNode
        :type q: TreeNode
        :rtype: bool
        """
        if not p and not q:
            return True
        if not p or not q:
            return False
        if p.val != q.val:
            return False

        left_equal = self.is_same_tree(p.left, q.left)
        right_equal = self.is_same_tree(p.right, q.right)

        return left_equal and right_equal


# Test cases
sol = Solution()

p = TreeNode(1)
p.left = TreeNode(2)
p.right = TreeNode(3)
q = TreeNode(1)
q.left = TreeNode(2)
q.right = TreeNode(3)

assert sol.is_same_tree(p, q)

p = TreeNode(1)
p.left = TreeNode(2)
q = TreeNode(1)
q.left = None
q.right = TreeNode(2)

assert not sol.is_same_tree(p, q)

p = TreeNode(1)
p.left = TreeNode(2)
p.right = TreeNode(1)
q = TreeNode(1)
q.left = TreeNode(1)
q.right = TreeNode(2)

assert not sol.is_same_tree(p, q)