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19 Remove Nth Node From End of List — Leetcode Problem, Javascript Solution

Remove Nth Node From End of List
Medium
Given a linked list, remove the n-th node from the end of list and return its head.
Example:
Given linked list: 1->2->3->4->5, and n = 2.

After removing the second node from the end, the linked list becomes 1->2->3->5.
Note:
Given n will always be valid.
Follow up:
Could you do this in one pass?
const rn = (head, n) => {
  let rv = 0;
  if (head) {
    rv = rn(head.next, n);
  }
  if (rv<n) {
    rv++;
    return rv;
  } else if(rv === n) {
    return head
  } else {
    head.next = head.next.next;
    return -Infinity;
  }
}

var removeNthFromEnd = function(head, n) {
  let result = rn(head, n);
  return head;
};
Run the code here: https://repl.it/@VinitKhandelwal/19-Leetcode-Javascript-Remove-Nth-Node-From-End-of-List

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