TidyNumbers.scala

package Main

import java.io.{FileInputStream, FileOutputStream}

import scala.io.StdIn


object Main2 extends App {
    Console.setIn(new FileInputStream("example2.in"))

    Console.setIn(new FileInputStream("B-small-practice.in"))
    Console.setOut(new FileOutputStream("B-small-practice.out"))

    Console.setIn(new FileInputStream("B-large-practice.in"))
    Console.setOut(new FileOutputStream("B-large-practice.out"))

    def solve(number: Long, last: Long = 0): Long = {
        if (last == number) {
            number
        } else {
            val numbers = number.toString.toCharArray

            def _solve(idx:Int = 0, acc: List[Char] = List()): List[Char] = {
                val c = numbers(idx)
                if (idx + 1 >= numbers.length) {
                    acc :+ numbers(idx)
                } else {
                    if (c > numbers(idx + 1)) {
                        (acc :+ (c - 1).toChar) ++ ("9" * (numbers.length - idx - 1)).toCharArray
                    } else {
                        _solve(idx + 1, acc :+ c)
                    }
                }
            }
            solve(_solve().mkString.toLong, number)
        }
    }

    val cases = StdIn.readLine().toInt
    (1 to cases) foreach { i => {
        val number = StdIn.readLine().toLong
        println(s"Case #$i: ${solve(number)}")
    }
    }
}