Description
A binary tree is uni-valued if every node in the tree has the same value.
Given the root of a binary tree, return true if the given tree is uni-valued, or false otherwise.
Example 1:
Input: root = [1,1,1,1,1,null,1] Output: true
Example 2:
Input: root = [2,2,2,5,2] Output: false
Constraints:
- The number of nodes in the tree is in the range
[1, 100]. 0 <= Node.val < 100
Solution
Python3
# 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 isUnivalTree(self, root: Optional[TreeNode]) -> bool:
value = root.val
def go(node):
if not node: return True
if node.val != value: return False
return go(node.left) and go(node.right)
return go(root)