partition n = part n $ map (:[]) [1..n] where part n [] = [] part n (x:xs) | s == n = x: r | s > n = r | otherwise = foldr (:) (part n $ map (:x) [h..n-1]) r where h = head x s = sum x r = part n xs
Main> partition 4 [[4],[2,2],[3,1],[2,1,1],[1,1,1,1]] -- I guess the order doesn't matter here. I myself is a newbie to Haskell. Every time I finished some code like this I was amazed at the elegance and expressiveness of the language. It's simply a different experience which you can't get from C/C++. I hope you have spent enough time on it before you look at this, otherwise you just missed some fun Haskell/homework/life has offered you:-) Cheers, Fan On 11/24/05, whoals (sent by Nabble.com) <[EMAIL PROTECTED]> wrote: > A partition of a positive integer n is a representation of n as the sum of > any number of positive integral parts. For example, there are 7 partitions > of the number 5: 1+1+1+1+1, 1+1+1+2, 1+1+3, 1+2+2, 1+4, 2+3 and 5. Define a > function parts which returns the list of distinct partitions of an integer > n. For example, parts 4 = > [[1,1,1,1],[1,1,2],[1,3],[2,2],[4]]. > ________________________________ > Sent from the Haskell - Haskell-Cafe forum at Nabble.com. > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > > > _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe