List replication problem from Hacker rank

Question

Problem:

Given a list, repeat each element in the list n amount of times.

Solution:

def listReplication(num:Int,arr:List[Int]):List[Int] = {
      arr.flatMap(each => (1 to num).map(n => each))
}

Need review.

Answer 1

Use scala.collection.generic.SeqFactory.fill(n:Int)(elem: =>A) instead of your self written one:

def listReplication(num:Int,arr:List[Int]):List[Int] = {
      arr.flatMap(each => List.fill(num)(each))
}

Also note that listReplication is a nice candidate for generics:

def listReplication[A](num:Int,arr:List[A]):List[A] = {
      arr.flatMap(each => List.fill(num)(each))
}

That way you can also handle lists that contain something else than Int.