LeetCode: Convert Sorted List To Binary Search Tree Solution

1/**
2 * Definition for singly-linked list.
3 * function ListNode(val, next) {
4 *     this.val = (val===undefined ? 0 : val)
5 *     this.next = (next===undefined ? null : next)
6 * }
7 */
8/**
9 * Definition for a binary tree node.
10 * function TreeNode(val, left, right) {
11 *     this.val = (val===undefined ? 0 : val)
12 *     this.left = (left===undefined ? null : left)
13 *     this.right = (right===undefined ? null : right)
14 * }
15 */
16/**
17 * @param {ListNode} head
18 * @return {TreeNode}
19 */
20var sortedListToBST = function (head) {
21  var sortedArrayToBST = function (nums) {
22    if (nums.length === 0) {
23      return null
24    }
25
26    const mid = Math.floor(nums.length / 2)
27    const node = new TreeNode(nums[mid])
28    node.left = sortedArrayToBST(nums.slice(0, mid))
29    node.right = sortedArrayToBST(nums.slice(mid + 1))
30
31    return node
32  }
33
34  const nums = []
35  while (head) {
36    nums.push(head.val)
37    head = head.next
38  }
39
40  return sortedArrayToBST(nums)
41}