# 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 isUniValSubStree(self, node: TreeNode) -> bool:
if node.right is None and node.left is None:
self.count += 1
return True
is_uni = True
if node.left:
is_uni = self.isUniValSubStree(node.left) and is_uni and node.left.val == node.val
if node.right:
is_uni = self.isUniValSubStree(node.right) and is_uni and node.right.val == node.val
if is_uni:
self.count += 1
return is_uni
def countUnivalSubtrees(self, root: TreeNode) -> int:
if not root:
return 0
self.count = 0
self.isUniValSubStree(root)
return self.count
