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{-# LANGUAGE BangPatterns, CPP, MagicHash, UnboxedTuples, TupleSections #-}
module Main (main) where
import Data.List (group)
import Data.Bits
import Data.Word
import Data.Maybe
import Control.Monad
import GHC.Word
import GHC.Base
import GHC.Num.Integer
import GHC.Num.Natural
import qualified GHC.Num.Integer as I
recipModInteger :: Integer -> Natural -> Maybe Natural
recipModInteger x m = case I.integerRecipMod# x m of
(# y | #) -> Just y
(# | () #) -> Nothing
main :: IO ()
main = do
let
f x = case recipModInteger x (2*3*11*11*17*17) of
y -> fmap (x,) y
-- positive modulo
print $ mapMaybe f [-7..71]
-- modulo == 1 or 0
print (recipModInteger 77 1)
print (recipModInteger 77 0)
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