Task

Create a program to parse a single five card poker hand and rank it according to this list of poker hands.



A poker hand is specified as a space separated list of five playing cards.

Each input card has two characters indicating face and suit.



Example

2d       (two of diamonds).


Faces are:    a, 2, 3, 4, 5, 6, 7, 8, 9, 10, j, q, k

Suits are:    h (hearts),   d (diamonds),   c (clubs),   and   s (spades),   or

alternatively,   the unicode card-suit characters:     ♥ ♦ ♣ ♠ 



Duplicate cards are illegal.

The program should analyze a single hand and produce one of the following outputs:

 straight-flush
 four-of-a-kind
 full-house
 flush
 straight
 three-of-a-kind
 two-pair
 one-pair
 high-card
 invalid



Examples

   2♥ 2♦ 2♣ k♣ q♦:   three-of-a-kind
   2♥ 5♥ 7♦ 8♣ 9♠:   high-card
   a♥ 2♦ 3♣ 4♣ 5♦:   straight
   2♥ 3♥ 2♦ 3♣ 3♦:   full-house
   2♥ 7♥ 2♦ 3♣ 3♦:   two-pair
   2♥ 7♥ 7♦ 7♣ 7♠:   four-of-a-kind 
   10♥ j♥ q♥ k♥ a♥:  straight-flush
   4♥ 4♠ k♠ 5♦ 10♠:  one-pair
   q♣ 10♣ 7♣ 6♣ q♣:  invalid

The programs output for the above examples should be displayed here on this page.



Extra credit

 use the playing card characters introduced with Unicode 6.0 (U+1F0A1 - U+1F0DE).
 allow two jokers
 use the symbol   joker
 duplicates would be allowed (for jokers only)
 five-of-a-kind would then be the highest hand


More extra credit examples

   joker  2♦  2♠  k♠  q♦:     three-of-a-kind
   joker  5♥  7♦  8♠  9♦:     straight
   joker  2♦  3♠  4♠  5♠:     straight
   joker  3♥  2♦  3♠  3♦:     four-of-a-kind
   joker  7♥  2♦  3♠  3♦:     three-of-a-kind
   joker  7♥  7♦  7♠  7♣:     five-of-a-kind
   joker  j♥  q♥  k♥  A♥:     straight-flush
   joker  4♣  k♣  5♦ 10♠:     one-pair
   joker  k♣  7♣  6♣  4♣:     flush
   joker  2♦  joker  4♠  5♠:  straight
   joker  Q♦  joker  A♠ 10♠:  straight
   joker  Q♦  joker  A♦ 10♦:  straight-flush
   joker  2♦  2♠  joker  q♦:  four-of-a-kind



Related tasks

 Playing cards
 Card shuffles
 Deal cards_for_FreeCell
 War Card_Game
 Go Fish


val faces = "23456789TJQKA"
val suits = "CHSD"
sealed trait Card
object Joker extends Card
case class RealCard(face: Int, suit: Char) extends Card
val allRealCards = for {
  face <- 0 until faces.size
  suit <- suits
} yield RealCard(face, suit)
 
def parseCard(str: String): Card = {
  if (str == "joker") {
    Joker
  } else {
    RealCard(faces.indexOf(str(0)), str(1))
  }
}
 
def parseHand(str: String): List[Card] = {
  str.split(" ").map(parseCard).toList
}
 
trait HandType {
  def name: String
  def check(hand: List[RealCard]): Boolean
}
 
case class And(x: HandType, y: HandType, name: String) extends HandType {
  def check(hand: List[RealCard]) = x.check(hand) && y.check(hand)
}
 
object Straight extends HandType {
  val name = "straight"
  def check(hand: List[RealCard]): Boolean = {
    val faces = hand.map(_.face).toSet
    faces.size == 5 && (faces.min == faces.max - 4 || faces == Set(0, 1, 2, 3, 12))
  }
}
 
object Flush extends HandType {
  val name = "flush"
  def check(hand: List[RealCard]): Boolean = {
    hand.map(_.suit).toSet.size == 1
  }
}
 
case class NOfAKind(n: Int, name: String = "", nOccur: Int = 1) extends HandType {
  def check(hand: List[RealCard]): Boolean = {
    hand.groupBy(_.face).values.count(_.size == n) >= nOccur
  }
}
 
val allHandTypes = List(
  NOfAKind(5, "five-of-a-kind"),
  And(Straight, Flush, "straight-flush"),
  NOfAKind(4, "four-of-a-kind"),
  And(NOfAKind(3), NOfAKind(2), "full-house"),
  Flush,
  Straight,
  NOfAKind(3, "three-of-a-kind"),
  NOfAKind(2, "two-pair", 2),
  NOfAKind(2, "one-pair")
)
 
def possibleRealHands(hand: List[Card]): List[List[RealCard]] = {
  val realCards = hand.collect { case r: RealCard => r }
  val nJokers = hand.count(_ == Joker)
  allRealCards.toList.combinations(nJokers).map(_ ++ realCards).toList
}
 
def analyzeHand(hand: List[Card]): String = {
  val possibleHands = possibleRealHands(hand)
  allHandTypes.find(t => possibleHands.exists(t.check)).map(_.name).getOrElse("high-card")
}