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) <

[hidden email]> 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.

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