Convert Sorted Array to Binary Search Tree

LeetCode Q 108 - 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]

Solution:

Code:

public TreeNode sortedArrayToBST(int[] nums) {
  return dfs(nums, 0, nums.length - 1);
}

private TreeNode dfs(int[] nums, int left, int right) {
  if (left > right) return null;
  if (left == right) return new TreeNode(nums[left]);
  
  int mid = left + (right - left) / 2;
  TreeNode n = new TreeNode(nums[mid]);
  n.left = dfs(nums, left, mid - 1);
  n.right = dfs(nums, mid + 1, right);
  
  return n;
}