108.Convert_Sorted_Array_to_Binary_Search_Tree.js

/**
 * 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;
    if (nums.length === 1) return new TreeNode(nums[0])
    const rootIndex = Math.floor(nums.length / 2)
    const root = new TreeNode(nums[rootIndex])
    root.left = sortedArrayToBST(nums.slice(0, rootIndex))
    root.right = sortedArrayToBST(nums.slice(rootIndex + 1))
    return root;
};