Solution.py

"""

A binary tree is univalued if every node in the tree has the same value.
Return true if and only if the given tree is univalued.
 
Example 1:


Input: [1,1,1,1,1,null,1]
Output: true


Example 2:


Input: [2,2,2,5,2]
Output: false


 
Note:

The number of nodes in the given tree will be in the range [1, 100].
Each node's value will be an integer in the range [0, 99].


"""


# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution(object):
    def isUnivalTree(self, root):
        """
        :type root: TreeNode
        :rtype: bool
        """
        if root is None:
            return True
        if root.left is not None:
            if root.val != root.left.val:
                return False
        if root.right is not None:
            if root.val != root.right.val:
                return False
        return self.isUnivalTree(root.left) and self.isUnivalTree(root.right)