Yachida

object legalTender extends App {
    val yenCoins = List(1
                    ,5
                    ,10
                    ,50
                    ,100
                    ,500)
    val yenMax = 20
    
    def sumCoins(coins: List[Int], max: Int): Int = coins.map(_ * max).sum

Yachida

import java.text._
object dateCheck extends App {
    
    def isDate(str: String): Boolean = {
        val d = new SimpleDateFormat("yyyyMMdd")
        d.setLenient(false)
        try {
            d.parse("2000"+str)
            true
        } catch {