30 lines
558 B
Haskell
30 lines
558 B
Haskell
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from :: Int -> [Int]
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from x = x : from (x+1)
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-- take :: Int -> [a] -> [a]
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-- take 0 _ = []
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-- take n (x:xs) = x : take (n-1) xs
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drop_mult :: Int -> [Int] -> [Int]
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drop_mult x xs = filter (\y -> mod y x /= 0) xs
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dropall :: [Int] -> [Int]
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dropall (x:xs) = x : dropall (drop_mult x xs)
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primes :: [Int]
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primes = dropall (from 2)
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odds :: [Int]
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odds = 1 : map (+2) odds
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pHelper _ 1 = []
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pHelper (x:xs) y | rem y x == 0 = x : pHelper (x:xs) (div y x)
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| otherwise = pHelper xs y
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primeFactors :: Int -> [Int]
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primeFactors = pHelper primes
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