# 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 sameTree(self, p: Optional[TreeNode], q: Optional[TreeNode]) -> bool:

        # base case: if both are null nodes
        if not p and not q:
            return True

        # if both happen to be actual nodes
        if p and q:
            return (p.val == q.val) and self.sameTree(p.left, q.left) and self.sameTree(p.right, q.right)

        # if either of them is not a null node
        return False


    def isSubtree(self, root: Optional[TreeNode], subRoot: Optional[TreeNode]) -> bool:

        # base case: both are null-nodes
        if not root and not subRoot:
            return True

        # base case: either root is null or subroot is null
        # then return obviously return False
        if not root or not subRoot:
            return False

        # for rest of the cases when root is a node
        if self.sameTree(root, subRoot) or self.sameTree(root.left, subRoot) or self.sameTree(root.right, subRoot):
            return True

        return self.isSubtree(root.left, subRoot) or self.isSubtree(root.right, subRoot)