euler/054/poker.py

import operator

class InvalidCard(Exception):
    pass
class InvalidHand(Exception):
    pass

def unique_combinations(items, n):
    if n==0: yield []
    else:
        for i in xrange(len(items)):
            for cc in unique_combinations(items[i+1:],n-1):
                yield [items[i]]+cc



class Card:
    VALUES = {'T': 10, 'J': 11, 'Q': 12, 'K': 13, 'A': 14}
    SUITS = {'Hearts': 'H', 'Diamonds': 'D', 'Clubs': 'C', 'Spades': 'S'}
    def __init__(self, string):
        self.value = string[0]
        if self.value in '23456789':
            self.value = int(self.value)
        else:
            try:
                self.value = Card.VALUES[self.value]
            except KeyError as e:
                raise InvalidCard('Invalid value: {0}'.format(string))
        self.suit = string[1]
        if not self.suit in Card.SUITS.values():
            raise InvalidCard('Invalid suit: {0}'.format(string))
    def __cmp__(self, other):
        return cmp(self.value, other.value)
    def __repr__(self):
        val = self.value
        for k, v in Card.VALUES.iteritems():
            if self.value == v:
                val = k
        return str.format('{0}{1}', val, self.suit)

class Hand:
    HIGH_CARD = 0
    ONE_PAIR = 1
    TWO_PAIRS = 2
    THREE_OF_A_KIND = 3
    STRAIGHT = 4
    FLUSH = 5
    FULL_HOUSE = 6
    FOUR_OF_A_KIND = 7
    STRAIGHT_FLUSH = 8
    ROYAL_FLUSH = 9
    RANKS = [
        'High Card',
        'One Pair',
        'Two Pairs',
        'Three of a Kind',
        'Straight',
        'Flush',
        'Full House',
        'Four of a Kind',
        'Straight Flush',
        'Royal Flush'
    ]
    def __init__(self, cards):
        if len(cards) != 5:
            raise InvalidHand(cards)
        self.__rank = None
        self.__cards = sorted([Card(c) for c in cards], reverse=True)
        self.__values = []
        self.rank()
    def __repr__(self):
        return str.format("Cards: {0} Rank: '{1}' Values: {2}",
            [str(c.value) + c.suit for c in self.__cards],
            Hand.RANKS[self.rank()],
            self.values())
    def rank(self):
        if self.__rank:
            return self.__rank
        flush = True
        straight = False
        last = None
        merged = {}
        for c in self.__cards:
            if last:
                if flush and c.suit != last.suit:
                    flush = False
            last = c
            if c.value in merged:
                merged[c.value] = merged[c.value] + 1
            else:
                merged[c.value] = 1
        if (len(merged)) == 5:
            # All unique cards, check for a straight
            if self.__cards[0].value - self.__cards[4].value == 4:
                straight = True
            if self.__cards[4].value == 2 and self.__cards[1].value == 5 and self.__cards[0].value == 14:
                straight = True
                # Set the value of the ace to 1 and resort so hand comparisons work correctly
                self.__cards[0].value = 1
                self.__cards = sorted(self.__cards, reverse=True)
            if straight and flush:
                if self.__cards[0].value == 14:
                    self.__rank = Hand.ROYAL_FLUSH
                else:
                    self.__rank = Hand.STRAIGHT_FLUSH
            elif flush:
                self.__rank = Hand.FLUSH
            elif straight:
                self.__rank = Hand.STRAIGHT
            else:
                self.__rank = Hand.HIGH_CARD
            self.__values = [c.value for c in self.__cards]
        else:
            multiples = [m for m in sorted(merged.items(), key = operator.itemgetter(1), reverse = True) if m[1] > 1]
            if len(multiples) > 1:
                if multiples[0][1] == multiples[1][1]:
                    self.__rank = Hand.TWO_PAIRS
                else:
                    self.__rank = Hand.FULL_HOUSE 
            else:
                if multiples[0][1] > 3:
                    self.__rank = Hand.FOUR_OF_A_KIND
                elif multiples[0][1] == 3:
                    self.__rank = Hand.THREE_OF_A_KIND
                else:
                    self.__rank = Hand.ONE_PAIR
            mvalues = [m[0] for m in multiples]
            self.__values = mvalues + [c.value for c in self.__cards if c.value not in mvalues]

        return self.__rank
    def values(self):
        if not self.__values:
            self.rank()
        return self.__values
    @staticmethod
    def create_best_hand(cards):
        if len(cards) == 5:
            return Hand(cards)
        elif len(cards) < 5:
            raise InvalidHand
        else:
            return Hand.create_best_hand_smart(cards)
        return false
    @staticmethod
    def create_best_hand_bruteforce(cards):
        combos = unique_combinations(cards, 5)
        hands = [Hand(combo) for combo in combos]
        hands = sorted(hands, reverse=True)
        return hands[0]
    @staticmethod
    def create_best_hand_smart(cards):
        """
        TODO: Implement the following logic (or something better):
        
        * Find all flushes
        * Find all straights
        ** Return best hand present in both flushes and straights, if applicable
        * Find all sets
        ** Return best quads with top remaining card
        ** Find and return best full house
        ** Find and return best three of a kind with top remaining cards
        ** Find and return best two pair with top remaining cards
        ** Find and return best single pair with top remaining cards
        ** Return top 5 cards
        """
        cards = sorted([Card(c) for c in cards], reverse=True)
        
        # Get all flushes
        flushes = []
        for suit in Card.SUITS.values():
            suited = [str(c) for c in cards if c.suit == suit]
            if len(suited) >= 5:
                combos = unique_combinations(suited, 5)
                for combo in combos: flushes.append(Hand(combo))
        flushes = sorted(flushes, reverse=True)
        if (flushes and flushes[0].rank() >= Hand.STRAIGHT_FLUSH):
            # Straight flush! No need to check anything else
            return flushes[0]
        
        #Get all sets
        merged = {}
        for c in cards:
            if c.value in merged:
                merged[c.value] = merged[c.value] + 1
            else:
                merged[c.value] = 1
        multiples = [m for m in sorted(merged.items(), key = operator.itemgetter(1), reverse = True) if m[1] > 1]
        quads = [c[0] for c in multiples if c[1] == 4]
        quads = [c for c in cards if c.value in quads]
        trips = [c[0] for c in multiples if c[1] == 3]
        trips = [c for c in cards if c.value in trips]
        pairs = [c[0] for c in multiples if c[1] == 2]
        pairs = [c for c in cards if c.value in pairs]
        remaining = [c for c in cards if c.value not in [m[0] for m in multiples]]
        
        if quads:
            h = quads[:4]
            remaining = [c for c in cards if c.value not in [cc.value for cc in h]][:1]
            for r in remaining: h.append(r)
            return Hand([str(c) for c in h])
        if trips and pairs:
            # Get a full house together
            h = trips[:3]
            remaining = pairs[:2]
            for r in remaining: h.append(r)
            return Hand([str(c) for c in h])
        if flushes:
            # We've already got a flush, return it!
            return flushes[0]
        # Look for a straight!
        if trips:
            h = trips[:3]
            remaining = [c for c in cards if c.value not in [cc.value for cc in h]][:2]
            for r in remaining: h.append(r)
            return Hand([str(c) for c in h])
        if pairs:
            if len(pairs) > 2:
                h = pairs[:4]
                remaining = [c for c in cards if c.value not in [cc.value for cc in h]][:1]
                for r in remaining: h.append(r)
                return Hand([str(c) for c in h])
            else:
                h = pairs
                remaining = [c for c in cards if c.value not in [cc.value for cc in h]][:3]
                for r in remaining: h.append(r)
                return Hand([str(c) for c in h])
        
        
        return Hand.create_best_hand_bruteforce([str(c) for c in cards])
    def __cmp__(self, other):
        # Compare hand rankings
        result = cmp(self.rank(), other.rank())
        if (result == 0):
            # Compare hand values
            for i in range(len(self.values())):
                result = cmp(self.values()[i], other.values()[i])
                if (result != 0):
                    return result
        return result