28 lines
766 B
Haskell
28 lines
766 B
Haskell
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import Data.Function
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import Data.List
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import qualified Data.Set as S
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prims = fix (\f (x:xs) -> x:f (filter (\y -> rem y x /= 0) xs)) [2..]
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--permu :: Integer -> S.Set Integer
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permu :: Integer -> S.Set Integer
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permu = S.fromList . map read . permutations . show
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primsList = dropWhile (< 1000) $ takeWhile (< 10000) prims
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primsSet = S.fromList primsList
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candidates :: [[Integer]]
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candidates = map (\prim -> S.toList $ S.intersection primsSet (permu prim)) primsList
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candidates' = filter (\x -> 3 <= length x) candidates
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candidates'' = map sort candidates'
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--permu' :: [a] -> [[a]]
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permu' [] = []
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permu' (x:xs) = [map permu' y | y <- tails xs]
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--permu3 xs = filter (\(a:b:c:[]) -> a < b && b < c && b - a == c - b) $ nub $ map (take 3) $ permutations xs
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