27 lines
829 B
Haskell
27 lines
829 B
Haskell
-- Surprisingly there are only three numbers that can be written as the sum of fourth powers of their digits:
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--
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-- 1634 = 1^4 + 6^4 + 3^4 + 4^4
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-- 8208 = 8^4 + 2^4 + 0^4 + 8^4
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-- 9474 = 9^4 + 4^4 + 7^4 + 4^4
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--
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-- As 1 = 1^4 is not a sum it is not included.
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--
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-- The sum of these numbers is 1634 + 8208 + 9474 = 19316.
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--
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-- Find the sum of all the numbers that can be written as the sum of fifth powers of their digits.
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import Data.Char (digitToInt)
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sumNthPowerDigit :: Int -> Int -> Int
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sumNthPowerDigit p n = sum [x ^ p | x <- map digitToInt (show n)]
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equalsSumNthPowerDigit :: Int -> Int -> Bool
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equalsSumNthPowerDigit p n = n == sumNthPowerDigit p n
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main = do
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let result = sum $ filter (equalsSumNthPowerDigit 5) [10 .. 354295]
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putStrLn $
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"Project Euler, Problem 30\n"
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++ "Answer: "
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++ show result
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