02.Answer

/*
  Create a new LazyList[A] from taking the n first elements from this. We can achieve that by recursively
  calling take on the invoked tail of a cons cell. We make sure that the tail is not invoked unless
  we need to, by handling the special case where n == 1 separately. If n == 0, we can avoid looking
  at the lazy list at all.
*/
def take(n: Int): LazyList[A] = this match
  case Cons(h, t) if n > 1 => cons(h(), t().take(n - 1))
  case Cons(h, _) if n == 1 => cons(h(), empty)
  case _ => empty

/*
  Create a new LazyList[A] from this, but ignore the n first elements. This can be achieved by recursively calling
  drop on the invoked tail of a cons cell. Note that the implementation is also tail recursive.
*/
@annotation.tailrec
final def drop(n: Int): LazyList[A] = this match
  case Cons(_, t) if n > 0 => t().drop(n - 1)
  case _ => this