29 lines
793 B
Haskell
29 lines
793 B
Haskell
-- A Pythagorean triplet is a set of three natural numbers, a < b < c, for which,
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--
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-- a2 + b2 = c2
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--
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-- For example, 32 + 42 = 9 + 16 = 25 = 52.
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--
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-- There exists exactly one Pythagorean triplet for which a + b + c = 1000.
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--
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-- Find the product abc.
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module P009 (p009) where
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import Data.List (uncons)
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import Data.Maybe (fromJust)
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pythagoreanTriplet :: Int -> (Int, Int, Int)
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pythagoreanTriplet n = fst . fromJust $ uncons [(x, y, z) | x <- [1 .. n], y <- [x .. n], z <- [y .. n], x + y + z == n, x ^ (2 :: Int) + y ^ (2 :: Int) == z ^ (2 :: Int)]
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prodTriplet :: (Int, Int, Int) -> Int
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prodTriplet (x, y, z) = x * y * z
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p009 :: IO ()
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p009 = do
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let result = prodTriplet $ pythagoreanTriplet 1000
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putStrLn $
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"Project Euler, Problem 9\n"
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++ "Answer: "
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++ show result
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