-- Surprisingly there are only three numbers that can be written as the sum of fourth powers of their digits:
--
-- 1634 = 1^4 + 6^4 + 3^4 + 4^4
-- 8208 = 8^4 + 2^4 + 0^4 + 8^4
-- 9474 = 9^4 + 4^4 + 7^4 + 4^4
--
-- As 1 = 1^4 is not a sum it is not included.
--
-- The sum of these numbers is 1634 + 8208 + 9474 = 19316.
--
-- Find the sum of all the numbers that can be written as the sum of fifth powers of their digits.

import Data.Char (digitToInt)

sumNthPowerDigit :: Int -> Int -> Int
sumNthPowerDigit p n = sum [ x^p | x <- map digitToInt (show n) ]

equalsSumNthPowerDigit :: Int -> Int -> Bool
equalsSumNthPowerDigit p n = n == sumNthPowerDigit p n

main = do
    let result = sum $ filter (equalsSumNthPowerDigit 5) [10..354295]
    putStrLn $ "Project Euler, Problem 30\n"
        ++ "Answer: " ++ show result