From 3b6b65b08b16cde07a4d8870e829a8c4b5e5d773 Mon Sep 17 00:00:00 2001 From: Charles Date: Sun, 18 Aug 2019 11:54:32 +0200 Subject: haskell problem 30 --- haskell/030-digit_fifth_powers.hs | 32 ++++++++++++++++++++++++++++++++ haskell/wip/030-digit_fifth_powers.hs | 30 ------------------------------ 2 files changed, 32 insertions(+), 30 deletions(-) create mode 100644 haskell/030-digit_fifth_powers.hs delete mode 100644 haskell/wip/030-digit_fifth_powers.hs (limited to 'haskell') diff --git a/haskell/030-digit_fifth_powers.hs b/haskell/030-digit_fifth_powers.hs new file mode 100644 index 0000000..15c5ba2 --- /dev/null +++ b/haskell/030-digit_fifth_powers.hs @@ -0,0 +1,32 @@ +-- Digit fifth powers +-- +-- Problem 30 +-- Surprisingly there are only three numbers that can be written as the sum of fourth +-- powers of their digits: +-- +-- 1634 = 14 + 64 + 34 + 44 +-- 8208 = 84 + 24 + 04 + 84 +-- 9474 = 94 + 44 + 74 + 44 +-- As 1 = 14 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. + + +-- there is a limit but who cares (me but im lazy) +main = do + let pow5 = [x | x <- [2..300000], digitsSumPow 5 x == x] + -- print (pow5) + print (sum pow5) + +digitsSumPow :: Int -> Int -> Int +digitsSumPow power nb = sum $ map (^power) (digits nb) + +digits x = reverse $ revDigits x + +revDigits :: Int -> [Int] +revDigits 0 = [] +revDigits x = x `mod` 10 : revDigits (x `div` 10) + diff --git a/haskell/wip/030-digit_fifth_powers.hs b/haskell/wip/030-digit_fifth_powers.hs deleted file mode 100644 index 6cc8a49..0000000 --- a/haskell/wip/030-digit_fifth_powers.hs +++ /dev/null @@ -1,30 +0,0 @@ --- Digit fifth powers --- --- Problem 30 --- Surprisingly there are only three numbers that can be written as the sum of fourth --- powers of their digits: --- --- 1634 = 14 + 64 + 34 + 44 --- 8208 = 84 + 24 + 04 + 84 --- 9474 = 94 + 44 + 74 + 44 --- As 1 = 14 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. - - -main = do - print ( [x0 + x1 * 10 + x2 * 100 + x3 * 1000 | - x0 <- [0..9], x1 <- [0..9], x2 <- [0..9], x3 <- [1..9], - (sum $ map (^4) [x0, x1, x2, x3]) - == x0 + x1 * 10 + x2 * 100 + x3 * 1000]) - - print ( [x0 + x1 * 10 + x2 * 100 + x3 * 1000 + x4 * 10000 | - x0 <- [0..9], x1 <- [0..9], x2 <- [0..9], x3 <- [0..9], x4 <- [1..9], - (sum $ map (^5) [x0, x1, x2, x3, x4]) - == x0 + x1 * 10 + x2 * 100 + x3 * 1000 + x4 * 10000]) - --- allPower :: Int -> [Int] --- allPower -- cgit