Hackerrank `Apples and oranges` problem

ApplesAndOranges.scala

import java.io._
import java.math._
import java.security._
import java.text._
import java.util._
import java.util.concurrent._
import java.util.function._
import java.util.regex._
import java.util.stream._

object Solution {

    // Complete the countApplesAndOranges function below.
    def countApplesAndOranges(s: Int, t: Int, a: Int, b: Int, apples: Array[Int], oranges: Array[Int]): Unit = {

      def filterAndCount(es: Array[Int], f: Int => Boolean, z: Int): Int = es.filter(f).map(z + _).filter(c => s <= c && c <= t).length
      
      val applesOnTheHouse = filterAndCount(apples, _ >= 0, a)
      val orangesOnTheHouse = filterAndCount(oranges, _ <= 0, b)

      println(s"$applesOnTheHouse\n$orangesOnTheHouse")
    }

    def main(args: Array[String]): Unit = {
        val stdin = scala.io.StdIn

        val st = stdin.readLine.split(" ")

        val s = st(0).trim.toInt

        val t = st(1).trim.toInt

        val ab = stdin.readLine.split(" ")

        val a = ab(0).trim.toInt

        val b = ab(1).trim.toInt

        val mn = stdin.readLine.split(" ")

        val m = mn(0).trim.toInt

        val n = mn(1).trim.toInt

        val apples = stdin.readLine.split(" ").map(_.trim.toInt)

        val oranges = stdin.readLine.split(" ").map(_.trim.toInt)
        
        countApplesAndOranges(s, t, a, b, apples, oranges)
    }
}