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HomePureScript solution to Project Euler problem 8
2018-May-12 07:27
Problem details at Project Euler problem 8 page.
Test
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | module Euler008Test (euler8suite) where import Prelude import Data . BigInt (fromString) import Euler008 (euler8) import Test . Unit (TestSuite, suite, test) import Test . Unit . Assert as Assert euler8suite :: forall e . TestSuite e euler8suite = suite "Euler 8" do test "Warmup" do Assert . equal (fromString "5832" ) (euler8 4 ) test "Real" do Assert . equal (fromString "23514624000" ) (euler8 13 ) |
Solution
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 | module Euler008 (euler8) where import Prelude import Data . Array (catMaybes, drop , filter , foldl , length , take , ( : )) import Data . BigInt (BigInt, fromInt) import Data . Char . Unicode (isDigit) import Data . Foldable ( maximum ) import Data . Int (fromString) import Data . Maybe ( Maybe ) import Data . String (singleton, toCharArray) num1000 :: String num1000 = "" " 73167176531330624919225119674426574742355349194934 96983520312774506326239578318016984801869478851843 85861560789112949495459501737958331952853208805511 12540698747158523863050715693290963295227443043557 66896648950445244523161731856403098711121722383113 62229893423380308135336276614282806444486645238749 30358907296290491560440772390713810515859307960866 70172427121883998797908792274921901699720888093776 65727333001053367881220235421809751254540594752243 52584907711670556013604839586446706324415722155397 53697817977846174064955149290862569321978468622482 83972241375657056057490261407972968652414535100474 82166370484403199890008895243450658541227588666881 16427171479924442928230863465674813919123162824586 17866458359124566529476545682848912883142607690042 24219022671055626321111109370544217506941658960408 07198403850962455444362981230987879927244284909188 84580156166097919133875499200524063689912560717606 05886116467109405077541002256983155200055935729725 71636269561882670428252483600823257530420752963450 "" " digits :: Array Int digits = toCharArray num1000 # filter isDigit # map (fromString <<< singleton) # catMaybes groups :: forall a . Int - > Array a - > Array ( Array a) groups n a | length a < n = [] | otherwise = take n a : groups n ( drop 1 a) euler8 :: Int - > Maybe BigInt euler8 n = let mula = map fromInt >>> foldl ( * ) (fromInt 1 ) in groups n digits # map mula # maximum |