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refact factorize using array reverse and use already existent code #385

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refact factorize using array reverse and use already existent code #385

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a27cdb7
refact factorize using array reverse and already existent code
klarkc Sep 1, 2021
ec6f6ce
add missing reverse import
klarkc Sep 1, 2021
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20 changes: 6 additions & 14 deletions exercises/chapter4/test/no-peeking/Solutions.purs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@ module Test.NoPeeking.Solutions where

import Prelude
import Control.MonadZero (guard)
import Data.Array (catMaybes, cons, filter, find, head, last, length, nub, null, tail, (..))
import Data.Array (catMaybes, cons, filter, find, head, last, length, nub, null, tail, (..), reverse)
import Data.Foldable (foldl)
import Data.Int (rem, quot)
import Data.Maybe (Maybe(..), fromMaybe, maybe)
Expand Down Expand Up @@ -58,19 +58,11 @@ triples n = do

-- | Provide the prime numbers that, multiplied together, make the argument.
factorize :: Int -> Array Int
factorize n = factorize' 2 n []
where
factorize' :: Int -> Int -> Array Int -> Array Int
factorize' _ 1 result = result

factorize' divisor dividend result =
let
remainder = rem dividend divisor
in
if remainder == 0 then
factorize' (divisor) (quot dividend divisor) (cons divisor result)
else
factorize' (divisor + 1) dividend result
factorize n = do
f <- reverse $ factors n
fi <- reverse $ f
guard $ isPrime fi
pure fi

allTrue :: Array Boolean -> Boolean
allTrue bools = foldl (\acc bool -> acc && bool) true bools
Expand Down