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:
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Input: root = [1,1,1,1,1,null,1]
Output: true
Example 2:
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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
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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));
}
};