List Replication

// This function takes in a List, say {1,2,3,4,5}
// It also takes in an int, say 2
// the returning List[Int] should be filled with {1,1,2,2,3,3,4,4,5,5}

def f(num:Int, arr:List[Int]):List[Int] = {
    var x : List[Int] = List()
    arr.foreach(data => x ::: addXTimes(data, num))
    def addXTimes(value:Int, time:Int):List[Int] = {
        var y : List[Int] = List()
        if(time > 0) {
            y ::: addXTimes(value, time-1)
        }
        y
    }
    x
}