Task3.hs

module Task3 where

import System.IO
import Data.List
import Data.List.Split
import Data.Char (isDigit)

main :: IO ()
main = do
    --handle <- openFile "test1.txt" ReadMode
    handle <- openFile "task3.txt" ReadMode
    contents <- hGetContents handle
    let 
        splitted = map (splitOn ",") .  concatMap (splitOn ")") . splitOn "mul("
        --filtered = filter (\x -> (length x == 2) && (all isDigit $ head x) && (all isDigit $ last x) && (not . null $ head x) && (not . null $ last x))
        filtered = filter (\x -> case x of {[a,b] -> (all isDigit a) && (all isDigit b) && (not $ null a) && (not $ null b); _ -> False})
        readAndCalc = foldl1 (+) . map (\[x,y] -> (read x :: Int) * (read y :: Int))
        res1 = (readAndCalc . filtered . splitted) contents
        res2 = (readAndCalc . filtered . splitted . getEnabledParts) contents
    --print $ "Input: " ++ contents
    --print $ "splitted: " ++ (show $ splitted contents)
    --print $ "filtered: " ++ (show $ (filtered . splitted) contents)
    print $ "Part 1: " ++ (show res1)
    --print $ "EnabledParts: " ++ (getEnabledParts contents)
    print $ "Part 2: " ++ (show res2)
    hClose handle

getEnabledParts :: String -> String
getEnabledParts = concatMap head . map (splitOn "don't()") . splitOn "do()"