/// <summary>Creates a poker hand score from 5 cards.</summary>
/// <param name="cards">The 5 cards to get a poker hand from.</param>
/// <remarks>
/// See: http://en.wikipedia.org/wiki/List_of_poker_hands
/// </remarks>
public static PokerHand CreateFrom5(IEnumerable <Card> cards)
{
if (cards == null || cards.Count() != 5 || cards.Any(c => c.IsEmpty()))
{
throw new ArgumentException("Five cards are required.", "card");
}
var straight5432Ace = false;
var score = PokerHandType.HighCard;
var pairs = CardPairs.Create(cards);
var sets = pairs.Max;
var o = cards
.OrderByDescending(c => c)
.OrderByDescending(c => pairs[c.Height])
.ToList();
switch (sets)
{
case 4: score = PokerHandType.FourOfAKind; break;
case 3: score = o[3].Height == o[4].Height ? PokerHandType.FullHouse : PokerHandType.ThreeOfAKind; break;
case 2: score = o[2].Height == o[3].Height ? PokerHandType.TwoPair : PokerHandType.OnePair; break;
default:
var isFlush = o.All(c => o[0].Suit == c.Suit);
// Ace, 5,4,3,2
straight5432Ace = o[0].Height == 14 && o[1].Height == 5;
var straight = straight5432Ace || (o[0].Height - o[4].Height == 4);
if (straight)
{
score = isFlush ? PokerHandType.StraightFlush : PokerHandType.Straight;
}
else if (isFlush)
{
score = PokerHandType.Flush;
}
break;
}
return(new PokerHand()
{
tp = score,
c0 = o[straight5432Ace ? 1 : 0],
c1 = o[straight5432Ace ? 2 : 1],
c2 = o[straight5432Ace ? 3 : 2],
c3 = o[straight5432Ace ? 4 : 3],
c4 = o[straight5432Ace ? 0 : 4],
});
}
/// <summary>Creates card pairs based on set of cards.</summary>
/// <param name="cards">
/// The cards to determine the pair for.
/// </param>
public static CardPairs Create(IEnumerable<Card> cards)
{
var pairs = new CardPairs()
{
// [2] = 2, [14] = Ace
lookup = new int[15]
};
foreach (var c in cards)
{
pairs.lookup[c.Height]++;
}
return pairs;
}
/// <summary>Creates card pairs based on set of cards.</summary>
/// <param name="cards">
/// The cards to determine the pair for.
/// </param>
public static CardPairs Create(IEnumerable <Card> cards)
{
var pairs = new CardPairs()
{
// [2] = 2, [14] = Ace
lookup = new int[15]
};
foreach (var c in cards)
{
pairs.lookup[c.Height]++;
}
return(pairs);
}