Sunday, April 8, 2012

Spider Solitaire winning probabilities

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I think that what makes Spider Solitaire so intriguing to some of us is that it seems to have an unlimited number of configurations. Thus, it challenges us & there is no boredom. There are 8 decks of 13 cards. This means there are 104 (8 x 13) cards.  If there was an 8 suit game, the # of possibilities is 104 x 103 x 102 x ... x 1 (104 factorial = 104! = a huge #). In the 4 suit game there are 2 of each card in each suit. In the 2 suit game there are 4 of each card in each suit. In the 1 suit game there are 8 of each card in the suit. As the duplication increases, the odds of winning increase.

Following the rules I've chosen, I've had a win rate of about 88% of the 1 suit games, 56% of the 2 suit games, &  16% of the 4 suit games for quite a long time now.
I've started writing a computer program to play using those rules. When I've finished & it's played many games, I'll publish the results.

If you already have a program & it wins at least close to the above #s, I would appreciate knowing about it.