CS代考 – ** Faster Keymap implementation using hash tables. – cscodehelp代写 – INTERVIEW&CODEHELP

— ** Faster Keymap implementation using hash tables.
{-# LANGUAGE ScopedTypeVariables #-}
module KeymapTable
, fromList

import Data.Char (ord)
import GHC.Arr

import qualified KeymapList as L

— * Exercise 4: gather

gather :: Ix i => (i,i) -> [(i,a)] -> [(i,[a])]
gather = undefined

— Hashes and hash tables

type Hash = Int

data Keymap k v = HashTable
(Array Hash (L.Keymap k v)) — an array mapping hashes to keymap lists
Int — capacity
deriving Show

class Hashable a where
hash :: a -> Hash

hashMod :: Hashable a => a -> Int -> Hash
hashMod x cap = hash x `mod` cap

instance Hashable Char where
hash = ord

— * Exercise 5: hashing a list

instance Hashable a => Hashable [a] where
hash s = undefined

— * Exercise 6: fromList

fromList :: forall k v. (Eq k, Hashable k) => [(k, v)] -> Keymap k v
fromList kvs = HashTable arr2 capacity
capacity :: Int
capacity = length kvs

— * Exercise 6a: calculating the list-valued array
arr :: Array Hash [(k, v)]
arr = undefined

— * Exercise 6b: calculating the keymap-valued array
arr2 :: Array Hash (L.Keymap k v)
arr2 = undefined

— * Exercise 7: get/toList/size

get :: (Eq k, Hashable k) => k -> Keymap k v -> Maybe v
get = undefined

toList :: (Eq k, Hashable k) => Keymap k v -> [(k, v)]
toList = undefined

size :: Eq k => Keymap k a -> Int
size = undefined

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CS代考 – ** Faster Keymap implementation using hash tables. – cscodehelp代写