public class Solution
extends Object
965 - Univalued Binary Tree\.
Easy
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`