treeowl

zipRev :: [a] -> [b] -> [(a,b)]
zipRev xs ys = fr where
  (fr, allbs) = go [] allbs xs ys
  
  go acc ~(b':bs') (a:as) (b:bs) = ((a,b') : res, bss)
    where
      (res, bss) = go (b:acc) bs' as bs
  go acc _ _ _ = ([], acc)

treeowl

-- | This module defines a function that produces a complete binary tree
-- from a breadth-first list of its (internal) node labels. It is an
-- optimized version of an implementation by Will Ness that avoids
-- any "impossible" cases. See
--
-- https://stackoverflow.com/a/60561480/1477667

module Bftr (Tree (..), bft, list, deftest) where
import Data.Function (fix)
import Data.Monoid (Endo (..))

treeowl

{-# language GADTs, ScopedTypeVariables, DeriveTraversable #-}
module ChallengeTransform where
import Data.Typeable
import Data.Proxy
import Data.Coerce

data Scheme a where
  Res :: Typeable a => !(Proxy a) -> Scheme a
  Arg :: Typeable a => !(Proxy a) -> Scheme b -> Scheme (a -> b)

treeowl

{-# language EmptyCase #-}
{-# language FlexibleContexts #-}
{-# language FlexibleInstances #-}
{-# language InstanceSigs #-}
{-# language MultiParamTypeClasses #-}
{-# language PolyKinds #-}
{-# language QuantifiedConstraints #-}
{-# language ScopedTypeVariables #-}
{-# language StandaloneKindSignatures #-}
{-# language TypeApplications #-}

treeowl

{-# language BangPatterns #-}
{-# language LinearTypes #-}
{-# language GADTs #-}
{-# language StandaloneKindSignatures #-}
{-# language KindSignatures #-}
{-# language TypeApplications #-}
{-# language DataKinds #-}
{-# language ScopedTypeVariables #-}

-- | Pairing heap loosely based on one Donnacha Oisín Kidney wrote for