Am 09.09.2010 22:55, schrieb Wanas:
Hey all,
So I have a two part question (I'm new to haskell, so you can throw all
your mugs at me).
a) I want to write a function that generates lists of lists of size $n$.
All having the property that sum lst = sum [1..n].
a-1) After that, I want to remove all permutations. My idea of doing
this is to get all lists from the first function and create a new list
with the property that "if sorted list A is not in the list, add it."
b-2) I think that's too much questions, but I want to get the hang of
this quickly (it was kickass for the few things I've tried out).
Something like this?
import Data.List
newList :: Int -> [[Int]]
newList n = myNub
[ l | l <- undefined -- not really sure how you want
-- to generate these lists :)
, sum l == sum [1..n]
]
myNub :: (Ord a) => [[a]] -> [[a]]
myNub = nubBy (\a b -> sort a == sort b)
- Nils
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