| 1 | import Control.Monad |
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| 2 | import Data.List |
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| 3 | import Control.Concurrent |
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| 4 | import GHC.Conc |
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| 5 | |
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| 6 | splits xs = zip ( inits xs ) ( tails xs ) |
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| 7 | |
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| 8 | perms [] = return [] |
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| 9 | perms (x:xs) = do |
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| 10 | ys <- perms xs |
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| 11 | (pre,post) <- splits ys |
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| 12 | return $ pre ++ x:post |
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| 13 | |
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| 14 | main = void $ forM [ 1 :: Int .. ] $ \ e -> do |
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| 15 | ch <- newChan |
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| 16 | void $ forM [ 1 .. GHC.Conc.numCapabilities ] $ \ t -> |
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| 17 | writeChan ch $ length $ reverse $ perms $ take e [ t .. ] |
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| 18 | out <- forM [ 1 .. GHC.Conc.numCapabilities ] $ \ t -> readChan ch |
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| 19 | print ( e, out ) |
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