1
var removeNthFromEnd = function (head, n) {
2
  let start = new ListNode(0, head);
3
  let slow = start,
4
    fast = start;
5

6
  for (let i = 1; i <= n; i++) {
7
    fast = fast.next;
8
  }
9

10
  while (fast && fast.next) {
11
    slow = slow.next;
12
    fast = fast.next;
13
  }
14

15
  let nthNode = slow.next;
16
  slow.next = nthNode.next;
17

18
  return start.next;
19
};