# Univalued Binary Tree Problem

## Description

LeetCode Problem 965.

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:

``````1
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Input: root = [1,1,1,1,1,null,1]
Output: true
``````

Example 2:

``````1
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

## Sample C++ Code

``````1
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/**
* Definition for a binary tree node.
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode() : val(0), left(nullptr), right(nullptr) {}
*     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
*     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
bool isUnivalTree(TreeNode* root) {
if (root == NULL)
return true;
else if ((root->left == NULL) && (root->right == NULL))
return true;
else if (root->left == NULL)
return ((root->val == root->right->val) && isUnivalTree(root->right));
else if (root->right == NULL)
return ((root->val == root->left->val) && isUnivalTree(root->left));
else
return ((root->val == root->left->val) && (root->val == root->right->val) &&
isUnivalTree(root->left) && isUnivalTree(root->right));
}
};
``````