Partitions

partitions.scala

def partitions(n: Int): List[List[Int]] = partitionsGreaterThan(n, 1)

def partitionsGreaterThan(n: Int, m: Int): List[List[Int]] = n match {
    case _ if m > n => List()
    case _ if m == n => List(List(n))
    case _ if m < n =>
        val ns1 = partitionsGreaterThan(n - m, m).map { m :: _ }
        val ns2 = partitionsGreaterThan(n, m + 1)
        ns1 ::: ns2
}