18 lines
822 B
Haskell
18 lines
822 B
Haskell
{-# LANGUAGE BangPatterns #-}
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import Data.Function (on)
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import Data.Bits ((.&.))
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count :: Int -> (Int, Int) -> (Int, Int) -> (Int, Int) -> Int -> Int -> Int
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count divisor (factorA, factorB) (seedA, seedB) (divA, divB) acc times =
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if times == 0 then acc else
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let !nextA = nextMaskBy factorA divA seedA
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!nextB = nextMaskBy factorB divB seedB
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!eq = fromEnum $ ((==) `on` (.&. 0xffff)) nextA nextB
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in count divisor (factorA, factorB) (nextA, nextB) (divA, divB) (acc + eq) (times - 1)
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where
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nextMaskBy f d s = let t = (f * s) `mod` divisor in if (t .&. d) == 0 then t else nextMaskBy f d t
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main :: IO ()
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main = do
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print $ count 2147483647 (16807, 48271) (634, 301) (0, 0) 0 40000000
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print $ count 2147483647 (16807, 48271) (634, 301) (3, 7) 0 5000000 |