sortedArrayToBst.js

/**
Given an integer array nums where the elements are sorted in ascending order, convert it to a height-balanced binary search tree.

Example 1:
Input: nums = [-10,-3,0,5,9]
Output: [0,-3,9,-10,null,5]
Explanation: [0,-10,5,null,-3,null,9] is also accepted:

Example 2:
Input: nums = [1,3]
Output: [3,1]
Explanation: [1,null,3] and [3,1] are both height-balanced BSTs.

* Definition for a binary tree node.
* function TreeNode(val, left, right) {
*     this.val = (val===undefined ? 0 : val)
*     this.left = (left===undefined ? null : left)
*     this.right = (right===undefined ? null : right)
* }

* @param {number[]} nums
* @return {TreeNode}
*/

var sortedArrayToBST = function (nums) {
  if (nums.length == 0) return null;

  const root = new TreeNode();

  const mid = Math.floor(nums.length / 2);

  root.val = nums[mid];
  root.left = sortedArrayToBST(nums.slice(0, mid));
  root.right = sortedArrayToBST(nums.slice(mid + 1));

  return root;
};