三个月算法进阶--day58

class Solution:
    def isSubStructure(self, A: TreeNode, B: TreeNode) -> bool:
        def helper(a, b):
            if not b:
                return True
            if not a:
                return False
            if a.val != b.val:
                return False
            return helper(a.left, b.left) and helper(a.right, b.right)

        return bool(A and B) and (helper(A, B) or self.isSubStructure(A.left, B) or self.isSubStructure(A.right, B))