97024928af
part 2 doesn’t work, time to rewrite
41 lines
1.2 KiB
Haskell
41 lines
1.2 KiB
Haskell
{-# LANGUAGE OverloadedStrings #-}
|
|
|
|
import Data.List
|
|
import Data.List.Split
|
|
import Data.Maybe
|
|
import qualified Data.Text as T
|
|
|
|
main :: IO ()
|
|
main = do
|
|
input <- map lines . splitOn "\n\n" <$> readFile "input"
|
|
let toDigit = T.unpack . T.replace "10" ":" . T.pack
|
|
print $
|
|
sum $ zipWith (*) [1 ..] $ map (fromEnum . isOrdered 0 . map toDigit) input
|
|
let divider = ["[[6]]", "[[2]]"]
|
|
let sorted = sortBy mySort (divider ++ concat input)
|
|
print $ product $ map (+ 1) $ mapMaybe (`elemIndex` sorted) divider
|
|
|
|
isOrdered :: Int -> [String] -> Bool
|
|
isOrdered n [l:ls, r:rs]
|
|
| n < 0 && l == ',' = False
|
|
| n > 0 && r == ',' = True
|
|
| l == r = isOrdered n [ls, rs]
|
|
| l == ']' = (r /= ',') || isOrdered (succ n) [ls, r : rs]
|
|
| r == ']' = l == ',' && isOrdered (pred n) [l : ls, rs]
|
|
| l == '[' = r /= ']' && isOrdered (pred n) [ls, r : rs]
|
|
| r == '[' = l == ']' || isOrdered (succ n) [l : ls, rs]
|
|
| l == ',' = False
|
|
| r == ',' = True
|
|
| l > r = False
|
|
| l < r = True
|
|
| otherwise = False
|
|
isOrdered _ [[], _] = True
|
|
isOrdered _ [_, []] = False
|
|
isOrdered _ _ = True
|
|
|
|
mySort :: String -> String -> Ordering
|
|
mySort x y =
|
|
if isOrdered 0 [x, y]
|
|
then LT
|
|
else GT
|