Icelandjack

http://www.michaelburge.us/2017/09/27/delta-debugging-in-haskell.html

data HList f xs where
  HNil  :: HList f '[]
  HCons :: f a -> HList f as -> HList f (a ': as)

divideGeneral :: forall f a bs. Divisible f => (a -> HList Identity bs) -> (HList f bs -> f a)
divideGeneral f = \case
  HNil ->

fedelebron

{-# LANGUAGE FlexibleContexts #-}
import Data.Array.IArray (IArray, bounds)
import Data.Array.Unboxed (UArray)
import Data.Array.Base (unsafeAt)
import Data.Bits (popCount, testBit)

permanent :: (Integral a, IArray UArray a) => UArray (Int, Int) a -> a
permanent arr | n == m = (if even n then negate else id) (sum entries)
  where
    ((0, 0), (n, m)) = bounds arr