What does the following function do? What is the complexity? public void output() { Node ptr1 null, ptr2 = null, dup = null; ptr1= head; while (ptr1 != null && ptr1.next != null) { per2 = ptri; } while (ptr2.next != null) { if (ptrl.data == ptr2.next.data) { ptr2.next = ptr2.next.next; } else { ptr2 = ptr2.next; } } ptr1 = ptr1.next;