PickingUpChicks.scala

import java.io.FileOutputStream

import scala.io.Source

object PickingUpChicks {
  val INPUT = "B-large-practice.in"
  val OUTPUT = INPUT.takeWhile(_ != '.') + ".out2"


  def main(args: Array[String]): Unit = {
    val itr = Source.fromFile(INPUT).getLines()
    val sets = itr.next().toInt

    val writer = new FileOutputStream(OUTPUT)
//    val writer = Console.out
    try {
      Console.withOut(writer) {
        for (set <- 1 to sets) {
          val Array(n,k,b,t) = itr.next().split(' ').map(_.toInt)
          val x = itr.next().split(' ').map(_.toInt)
          val v = itr.next().split(' ').map(_.toInt)
          println(f"Case #${set}: ${solve(n,k,b,t,x,v)}")
        }
      }
    } finally {
      writer.close()
    }
  }

  def solve(n:Int, k:Int, barn:Int, time:Int, pos:Array[Int], v:Array[Int]) = {
    def inner(n:Int, k:Int, swapCnt:Int = 0, impossibleChks:Int = 0): Option[Int]= (n,k) match {
      case (_, 0) => Some(swapCnt)
      case (0, _) => None
      case _ if((barn - pos(n-1)) <= v(n-1) * time) => inner(n-1, k-1, swapCnt + impossibleChks, impossibleChks)
      case _ => inner(n-1, k, swapCnt, impossibleChks + 1)
    }
    inner(n,k).getOrElse("IMPOSSIBLE")
  }
}