• https://leetcode.com/problems/remove-nth-node-from-end-of-list/
• 19. Remove Nth Node From End of List

JavaScript 解答

var removeNthFromEnd = function (head, n) {
    if (!head) return head;
    var len = 0;
    var tail = head;
    while (tail) {
        tail = tail.next;
        len++;
    }
    if (len === n) {
        return head.next;
    }

    len = len - n - 1;
    tail = head;
    while (len) {
        tail = tail.next;
        len--;
    }
    tail.next = tail.next.next;
    return head;
};

Ruby 解答

def remove_nth_from_end(head, n)
  p=r=head
  n.times{ p=p.next }
  return head.next if p==nil
  (r=r.next;p=p.next) while p.next!=nil
  r.next=r.next.next
  head
end