LeetCode in Kotlin
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
Solution
import com_github_leetcode.TreeNode
import java.util.LinkedList
/*
* Example:
* var ti = TreeNode(5)
* var v = ti.`val`
* Definition for a binary tree node.
* class TreeNode(var `val`: Int) {
* var left: TreeNode? = null
* var right: TreeNode? = null
* }
*/
class Solution {
fun isUnivalTree(root: TreeNode?): Boolean {
val `val`: Int = root!!.`val`
val queue: LinkedList<TreeNode?> = LinkedList<TreeNode?>()
queue.add(root)
while (queue.isNotEmpty()) {
val node: TreeNode? = queue.poll()
if (node!!.`val` != `val`) {
return false
}
if (node.left != null) {
queue.add(node.left)
}
if (node.right != null) {
queue.add(node.right)
}
}
return true
}
}