572. Subtree of Another Tree

solution.py

# 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 identical_tree(self, root: Optional[TreeNode], subRoot: Optional[TreeNode]):
        if root is None or subRoot is None:
            return root == subRoot

        if root.val != subRoot.val:
            return False

        return (
            self.identical_tree(root.left, subRoot.left) 
            and self.identical_tree(root.right, subRoot.right)
        )

    def isSubtree(self, root: Optional[TreeNode], subRoot: Optional[TreeNode]) -> bool:
        if root is None or subRoot is None:
            return root == subRoot

        if root.val == subRoot.val:
            is_identical = self.identical_tree(root, subRoot) 
            if is_identical:
                return True
        
        return (
            self.isSubtree(root.left, subRoot)
            or self.isSubtree(root.right, subRoot)
        )