Convert Sorted Array to Binary Search Tree

https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree

Given an array where elements are sorted in ascending order, convert it to a height balanced BST.

For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1.

Example:

Given the sorted array: [-10,-3,0,5,9],

One possible answer is: [0,-3,9,-10,null,5], which represents the following height balanced BST:

      0
     / \
   -3   9
   /   /
 -10  5

Implementation :

/**
* Definition for a binary tree node.
* public class TreeNode {
*     int val;
*     TreeNode left;
*     TreeNode right;
*     TreeNode(int x) { val = x; }
* }
*/
class Solution {
   public TreeNode sortedArrayToBST(int[] nums) {
       if(nums == null || nums.length == 0)
           return null;
       return constructTree(nums, 0, nums.length - 1);
   }
   
   public TreeNode constructTree(int[] nums, int left, int right){
       if(left > right)
           return null;
       int mid = left + (right - left) / 2;
       TreeNode node = new TreeNode(nums[mid]);
       node.left = constructTree(nums, left, mid -1);
       node.right = constructTree(nums, mid+1, right);
       return node;
   }
}

References :

1. https://www.youtube.com/watch?v=PZYTs9y4f4o
2. https://www.youtube.com/watch?v=12omz-VAyRk