Var length generator

A

def gen(n: Int, limit: Int, k: Int = 1): Iterator[List[Int]] = {
  val range = (k until limit).iterator
  n match {
    case _ if n > 0 => for {
      x <- range
      y <- gen(n - 2, limit, x)
    } yield x :: y
    case _ => range.map(List(_))
  }
}

B

def gen(n: Int, limit: Int, k: Int = 1): Iterator[List[Int]] =
  val range = (k until limit).iterator
  if (n > 0) {
    for {
      x <- range
      y <- gen(n - 2, limit, x)
    } yield x :: y
  } else {
    range.map(List(_))
  }
}