Convert Sorted Array to Binary Search Tree - LeetCode

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

Java Solution :

/**
 * 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 constructarraytobst(nums,0,nums.length-1);  
    }
    
    public TreeNode constructarraytobst(int[] nums , int left , int right){
        if(left > right)
          return null;
        
        int mid = left + (right-left)/2;
        TreeNode current = new TreeNode(nums[mid]);
        current.left = constructarraytobst(nums,left,mid-1);
        current.right = constructarraytobst(nums,mid+1,right);
        return current;
    }
}