An answer of http://nabetani.sakura.ne.jp/hena/ord14linedung/

monster.scala

// An answer of http://nabetani.sakura.ne.jp/hena/ord14linedung/

import scala.io._

object Monster 
{
  def isLessThan(c1:Char, c2:Char) = c1.toString.toUpperCase < c2.toString.toUpperCase

  def solve(src:String) = { 
    var s = src.sortWith((x, y) => isLessThan(x, y)) 
    ("aBcDeFgHiJkL" * 2).grouped(2).toList.map(arg => {
      if(s.indexOf(arg) == -1) {
        0   
      } else {
        val count = s.count(_ == arg(1))
        val lookup = Map("aB"->"c", "cD"->"e", "eF"->"g", "gH"->"i", "iJ"->"k", "kL"->"a")
        s = s.replace(arg, lookup(arg)).filter(_ != arg(1)).sortWith((x, y) => isLessThan(x, y)) 
        count
      }   
    }).reduceLeft((x, y) => x + y).toString
  }

  def main(args:Array[String]) = { 
    Source.fromInputStream(System.in).getLines.foreach(arg => {
      val Array(src, expected) = arg.split(" ")
      val actual = solve(src)
      println(src + " => " + (if(expected == actual) "ok" else "***NG***"))
    })  
  }
}