scala twoliner
```scala []
object Solution {
  def miceAndCheese(reward1: Array[Int], reward2: Array[Int], k: Int): Int = {
    lazy val diffMap = (reward1.to(List) zip reward2).map{case (a,b) => a-b}.zipWithIndex
      .sorted.reverse.take(k).map(_.swap).to(Map).withDefaultValue(0)
    reward2.iterator.zipWithIndex.map{case (r,i) => r+diffMap(i)}.sum
  }
}
```
['Scala']