[ネタ] どう書くポーカーのScala 版

ParserMain.scala

// solution to http://qiita.com/items/cbc3af152ee3f50a822f
// using parser combinators

import scala.util.parsing.combinator.RegexParsers

case class Card(suit: String, rank: String)

trait CardsParser extends RegexParsers {
  def cards = repN(5, card)
  def card: Parser[Card] = (suit ~ rank) ^^ {case s~r => Card(s, r)}
  def suit: Parser[String] = "[SHDC]".r
  def rank: Parser[String] = "[A2-9JQK]|10".r
}

object Main extends App with CardsParser {
  val hand: String => String = Map(
    "14" -> "4K", "23" -> "FH", "113" -> "3K",
    "122" -> "2P", "1112" -> "1P", "11111" -> "--")
  
  def toHand(cards: List[Card]): String =
    hand(cards.groupBy(_.rank).map(_._2.length).toSeq.sorted.mkString)
  
  def solve(deal: String): String =
    parseAll(cards, deal).map(toHand).getOrElse("Parse Error!")
  
  // test cases are taken from http://gist.github.com/3026343  
  assert(solve("DASAD10CAHA")   == "4K")
  assert(solve("S10HJDJCJSJ")   == "4K")
  assert(solve("S10HAD10DAC10") == "FH")
  assert(solve("HJDJC3SJS3")    == "FH")
  assert(solve("S3S4H3D3DA")    == "3K")
  assert(solve("S2HADKCKSK")    == "3K")
  assert(solve("SASJDACJS10")   == "2P")
  assert(solve("S2S10H10HKD2")  == "2P")
  assert(solve("CKH10D10H3HJ")  == "1P")
  assert(solve("C3D3S10SKS2")   == "1P")
  assert(solve("S3SJDAC10SQ")   == "--")
  assert(solve("C3C9SAS10D2")   == "--")
}

SimpleMain.scala

// simple scala solution to http://qiita.com/items/cbc3af152ee3f50a822f

object Main extends App {
  val hand: String => String = Map(
    "14" -> "4K", "23" -> "FH", "113" -> "3K",
    "122" -> "2P", "1112" -> "1P", "11111" -> "--")
  
  def solve(deal: String) =
    hand("[A2-9JQK]|10".r.findAllIn(deal).toSeq.groupBy(identity)
        .map(_._2.length).toSeq.sorted.mkString)

  // test cases are taken from http://gist.github.com/3026343
  assert(solve("DASAD10CAHA")   == "4K")
  assert(solve("S10HJDJCJSJ")   == "4K")
  assert(solve("S10HAD10DAC10") == "FH")
  assert(solve("HJDJC3SJS3")    == "FH")
  assert(solve("S3S4H3D3DA")    == "3K")
  assert(solve("S2HADKCKSK")    == "3K")
  assert(solve("SASJDACJS10")   == "2P")
  assert(solve("S2S10H10HKD2")  == "2P")
  assert(solve("CKH10D10H3HJ")  == "1P")
  assert(solve("C3D3S10SKS2")   == "1P")
  assert(solve("S3SJDAC10SQ")   == "--")
  assert(solve("C3C9SAS10D2")   == "--")  
}