572. Subtree of Another Tree

# 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 isSubtree(self, s: TreeNode, t: TreeNode) -> bool:
        if s:
            return self.isMatch(s, t) or self.isSubtree(s.left, t) or self.isSubtree(s.right, t)
        else:
            return False

    def isMatch(self, s, t):
        if (s and not t) or (t and not s):
            return False
        elif not t and not s:
            return True

        if s.val == t.val:
            if self.isMatch(s.left, t.left) and self.isMatch(s.right, t.right):
                return True
            else:
                return False