[Haskell-cafe] Slow IO?

[Eugene Kirpichov]

Hm, on my machine Don's code has exactly the same performance my code above.

Also, replacing the 'test' and 'parse' functions with this one

add :: Int -> Int -> S.ByteString -> Int
add k i s = fst $ S.foldl' f (i, 0) s
  where f (!i, !n) '\n' | n`divisibleBy`k = (i+1, 0)
                        | otherwise       = (i,   0)
        f (!i, !n) w  = (i, 10*n+ord w-ord '0')

increases performance by another 15% (0.675s vs 0.790s)

2009/9/1 Jason Dusek <jason.dusek at gmail.com>:
>  I've updated Don Stewart's solution to compile with the modern
>  ByteString libs. I'll be looking at ways to improve the
>  performance of the `bytestring-nums` package.
>
> --
> Jason Dusek
>
>
> http://github.com/jsnx/bytestring-nums/blob/d7de9db83e44ade9958fb3bfad0b29ede065b5dd/SPOJDons.hs
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-- 
Eugene Kirpichov
Web IR developer, market.yandex.ru