# [Solved] 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. ## Question

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`

## Python Solution

```# 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: TreeNode) -> bool:
stack = [root]
prev = root.val
while len(stack)!=0:
x = stack.pop()
if x==None:
continue
curr = x.val
if prev!=curr:
return False
stack.append(x.left)
stack.append(x.right)
prev = curr

return True```