CTO challenge Level1

coupon.scala

/**
	* coupon.scala
	*
	* Usage:% scala couponopt.scala <支払総額> <50円の枚数> <100円の枚数> <500円の枚数>
	* 使用可能でかつ最小の枚数になる組み合わせを表示する
*/

object Coupon{
	def selectOptimalCoupons(total:Int, coupon:List[Int]) :Unit= {

		val valueList :List[Int] = List(50, 100, 500)

		def available(remain :Int, index :Int) :Unit= {
			val value = valueList(index)
			val amount = {
			if((remain / value) < coupon(index))
				 (remain / value)
			else coupon(index)
			}
			if(index>0){
				available( remain - amount * value , index - 1)
			}
			println( value + "円 : " + amount + "枚")
		}

		available(total, 2)
	}

	def main(args: Array[String]): Unit = {
		args.length match {
			case 4 =>
				val argsToInt = args.map(_.toInt)
				selectOptimalCoupons(argsToInt.head, argsToInt.tail.toList)
			case _ => println(
				"Usage:\"scala coupon.scala <¥total> <# of ¥500> <# of ¥100> <# of ¥50>\"")
		}
	}
}