CareerCup

Classic!

enum Suit { SPADES, CLUBS, HEARTS, DIAMONDS, };
enum Face { ACE, TWO, THREE, FOUR, FIVE, SIX, SEVEN, EIGHT, NINE, TEN, JACK, QUEEN, KING, };

class Card {
public:
    Card(Suit suit, Face face) : suit(suit), face(face) {}
    Card(const Card& orig) : suit(orig.suit), face(orig.face) {}
    Suit getSuit() const { return suit; }
    Face getFace() const { return face; }
private:
    Card() {}
    Suit suit;
    Face face;
    friend class Deck;
};

class Deck {
public:
    Deck() {
        int index = 0;
        for (int i = 0; i < SUITS_PER_DECK; ++i) {
            for (int j = 0; j < CARDS_PER_SUIT; ++j) {
                index = i * CARDS_PER_SUIT + j;
                cards[index].suit = (Suit) i;
                cards[index].face = (Face) j;
            }
        }
    }

    Deck(const Deck& orig) {
        for (int i = 0; i < SUITS_PER_DECK * CARDS_PER_SUIT; ++i) {
            cards[i] = orig.cards[i];
        }
    }

    void Shuffle() {
        int bagSize = SUITS_PER_DECK * CARDS_PER_SUIT;
        int index = 0;
        srand(time(NULL));
        while (bagSize) {
            index = rand() % bagSize;
            swap(cards[--bagSize], cards[index]);
        }
    }

    static const int SUITS_PER_DECK = 4;
    static const int CARDS_PER_SUIT = 13;
private:
    Card cards[SUITS_PER_DECK * CARDS_PER_SUIT];
    friend ostream & operator<<(ostream&, const Deck&);
};

private void Shuffle(int seed)
{
Random r = new Random(seed);
for(int i=51; i>0;i--)
{
int x = r.nextInt(i); // picks from 0...i
swap cards x and i;
}

}

One simple solution is, assign random number to each card. and then sort the deck.

excellent work above. Thanks.

You're welcome.
About the shuffle method, mine does it in O(n), sorting will do it in O(nlogn)

simple and smartest solution is to assign random number ( as some one already mentioned) and then make a BST of those numbers...so we're done in O(n)...as traversing the full list takes no more than O(n)...done!

isnt it that in shuffle, ith cell goes to (2i%l) th position ?

@bebo ??????

test case guys : when after shuffling comes back to original state.

@ Anonymous :

Cool Stuff bro/sis!!!

x=0;
while input list empty {
  r= Random(x,n)
  Place rth element in xth position of the output list
  Delete entry for rth element in the input list
  x++
}
return output list.

Help me know the pitfall of this approach.

@Ankush Bindlish on September 04, 2009:
I guess you're not supposed to delete the element at the rth position as in that case you loose that element, so I guees you meant exchange the elements at x and r positions. right???