module BishBosh.Data.Foldable(
findDuplicates
) where
import qualified Data.Foldable
import qualified Data.Map.Strict as Map
findDuplicates :: (Foldable foldable, Ord a) => foldable a -> [a]
findDuplicates :: foldable a -> [a]
findDuplicates = Map a Int -> [a]
forall k a. Map k a -> [k]
Map.keys (Map a Int -> [a])
-> (foldable a -> Map a Int) -> foldable a -> [a]
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Int -> Bool) -> Map a Int -> Map a Int
forall a k. (a -> Bool) -> Map k a -> Map k a
Map.filter (Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
> Int
1) (Map a Int -> Map a Int)
-> (foldable a -> Map a Int) -> foldable a -> Map a Int
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (a -> Map a Int -> Map a Int)
-> Map a Int -> foldable a -> Map a Int
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
Data.Foldable.foldr (
(a -> Int -> Map a Int -> Map a Int)
-> Int -> a -> Map a Int -> Map a Int
forall a b c. (a -> b -> c) -> b -> a -> c
flip ((Int -> Int -> Int) -> a -> Int -> Map a Int -> Map a Int
forall k a. Ord k => (a -> a -> a) -> k -> a -> Map k a -> Map k a
Map.insertWith ((Int -> Int -> Int) -> a -> Int -> Map a Int -> Map a Int)
-> (Int -> Int -> Int) -> a -> Int -> Map a Int -> Map a Int
forall a b. (a -> b) -> a -> b
$ (Int -> Int) -> Int -> Int -> Int
forall a b. a -> b -> a
const Int -> Int
forall a. Enum a => a -> a
succ) (Int
1 :: Int)
) Map a Int
forall k a. Map k a
Map.empty