// Top and bottom N max/min items from an Array, with no need to sort

output.txt

----------
541
141
18
----------
540
16
----------
-7
2
16
----------
17
540
----------
10000000
9999999
9999998
----------
10000000
9999999
9999998
----------
0
1
2

TopBottomN.scala

// Top and bottom N max/min items from an Array, with no need to sort

object TopBottomN extends App {

  def bottomN(a: Array[Int], n: Int): Array[Int] = {
    val smallestVals = Array.fill(n)(Int.MaxValue)

    a.foreach { number =>
      var inserted=false
      (n - 1 to 0 by -1).foreach { pos =>
        if (smallestVals(pos) > number && !inserted) {
          (0 to pos - 1).foreach { x =>  smallestVals(x) = smallestVals(x + 1) }
          smallestVals(pos) = number
          inserted=true
        }
      }
    }

    smallestVals.filterNot(_==Int.MaxValue).reverse
  }

  def topN(a: Array[Int], n: Int): Array[Int] = {
    val largestVals = Array.fill(n)(Int.MinValue)

    a.foreach { number =>
      var inserted=false
      (n - 1 to 0 by -1).foreach { pos =>
        if (largestVals(pos) < number && !inserted) {
          (0 to pos - 1).foreach { x =>  largestVals(x) = largestVals(x + 1) }
          largestVals(pos) = number
          inserted=true
        }
      }
    }

    largestVals.filterNot(_==Int.MinValue).reverse

  }

  println("-"*10)
  topN(Array(141, 1, 17, -7, 18, 541), 3).foreach(println)

  println("-"*10)
  topN(Array(16, 540), 3).foreach(println)

  println("-"*10)
  bottomN(Array(131, 2, 16, -7, 18, 542), 3).foreach(println)

  println("-"*10)
  bottomN(Array(17, 540), 3).foreach(println)

  val bigNum=10000000

  println("-"*10)
  topN((0 to bigNum).toArray, 3).foreach(println)

  println("-"*10)
  topN((bigNum to 0 by -1).toArray, 3).foreach(println)

  println("-"*10)
  bottomN((0 to bigNum).toArray, 3).foreach(println)
}