Another attempt at Scala ranges challenge

gistfile1.scala

// This method works, but I'm trying to shrink it in the form further down..

def ranges(ints: Seq[Int]): Seq[(Int, Int)] = {
    ints.sorted.foldLeft( Seq[(Int,Int)]() )(
        (acc: Seq[(Int,Int)], n: Int) => acc match {
            case acc if (acc.nonEmpty) => acc.last match {
                case (a,z) if (z == n) => acc
                case (a,z) if (z+1 == n) => acc.init :+ (a, n)
                case _ => acc :+ (n,n)
            }
            case _ => acc :+ (n,n)
        }
    )
}



// This method doesn't work, because I can't seem to match against the last element in a list..

def ranges(ints: Seq[Int]): Seq[(Int, Int)] = {
    ints.sorted.foldLeft( Seq[(Int,Int)]() )(
        (acc: Seq[(Int,Int)], n: Int) => acc match {
            // case Nil => acc :+ (n,n)
            case x :: (a,z) if (z == n) => acc
            case x :: (a,z) if (z+1 == n) => x :+ (a, n)
            case _ => acc :+ (n,n)
        }
    )
}