Since there was just a golf for factorials, I figured that doing one for the number of ways to select M objects from a set of N objects without repetition might be appropriate.
Basically, if I have a set of 4 cards, how many ways can I select a hand of 1 card from the set without repeating myself? The answer is obviously 4. Now if I have a hand size of 2 how many ways are there? The answer is 6, but it is less obvious.
The general solution is defined by the function:
Where M is the size of the set and N is the number of cards to select. And M! is the factorial of M. See Golf: Factorials for more info.Choose(M, N) = M!  N! * (M  N)!
The following are test cases that you can use:
M  N  Answer  Notes 

52  5  2598960  Number of 5 card hands in a deck of 52 cards 
52  7  133784560  Number of 7 card hands in a deck of 52 cards 
52  13  635013559600  Number of 7 card hands in a deck of 52 cards 
52  52  1  Number of ways to select a hand size of 1 from a 52 card deck 
The interface for the resulting code should be:
print c($m, $n);
If you want to define a factorial subroutine that should be included in the size of the code.
ben


Replies are listed 'Best First'.  

Re: Golf: Selection from sets (Choose)
by no_slogan (Deacon) on May 25, 2001 at 00:42 UTC  
Re: Golf: Selection from sets (Choose)
by knobunc (Pilgrim) on May 24, 2001 at 21:56 UTC  
Re: Golf: Selection from sets (Choose)
by srawls (Friar) on May 24, 2001 at 22:44 UTC  
by tilly (Archbishop) on May 25, 2001 at 04:30 UTC  
Re: Golf: Selection from sets (Choose)
by jynx (Priest) on May 25, 2001 at 01:11 UTC 
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