import scala.collection.mutable.ArrayBuffer

 import scala.util.control.Breaks

 object Exchange {

   def delete(arg:ArrayBuffer[Int]):ArrayBuffer[Int]={

     val breakables = new Breaks

     breakables.breakable {

       for (i <- 0 until arg.length) {

         if (arg(i) == arg.max) {

           arg.remove(i)

           breakables.break()

         }

       }

     }

     arg

   }

   def exchange(total:Int,money:ArrayBuffer[Int]):Int={

     if (total==0)

       1

     else if(total<0||money.length==0)

       0

     else{

       //var newMoney=money这种赋值方式，newMoney其实不是一个新的数组

       val newMoney = for(elem <- money) yield elem

       delete(newMoney)

       exchange((total-money.max),money)+exchange(total,newMoney)

     }

   }

   def main(args:Array[String]): Unit ={

     val ab = ArrayBuffer[Int](50,20,10,5,2,1)

     println(exchange(100,ab))

   }

 }