module Combinatorics.Permutation.WithoutSomeFixpoints where
import Combinatorics (permute)
enumerate :: (Eq a) => Int -> [a] -> [[a]]
enumerate :: forall a. Eq a => Int -> [a] -> [[a]]
enumerate Int
k [a]
xs = forall a. (a -> Bool) -> [a] -> [a]
filter (forall (t :: * -> *). Foldable t => t Bool -> Bool
and forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a b c. (a -> b -> c) -> [a] -> [b] -> [c]
zipWith forall a. Eq a => a -> a -> Bool
(/=) [a]
xs forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a. Int -> [a] -> [a]
take Int
k) forall a b. (a -> b) -> a -> b
$ forall a. [a] -> [[a]]
permute [a]
xs
numbers :: (Num a) => [[a]]
numbers :: forall a. Num a => [[a]]
numbers =
forall a. [a] -> [a]
tail forall a b. (a -> b) -> a -> b
$ forall b a. (b -> a -> b) -> b -> [a] -> [b]
scanl (\[a]
row a
fac -> forall b a. (b -> a -> b) -> b -> [a] -> [b]
scanl (-) a
fac [a]
row) [] forall a b. (a -> b) -> a -> b
$
forall b a. (b -> a -> b) -> b -> [a] -> [b]
scanl forall a. Num a => a -> a -> a
(*) a
1 forall a b. (a -> b) -> a -> b
$ forall a. (a -> a) -> a -> [a]
iterate (a
1forall a. Num a => a -> a -> a
+) a
1