67 lines
2.1 KiB
Haskell
67 lines
2.1 KiB
Haskell
import Data.List
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import qualified Data.List.Split as S
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import Debug.Trace
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data PageNum = Page Integer [(Integer, Integer)]
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instance Num PageNum where
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(Page x r) + (Page y _) = Page (x+y) r
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(Page x r) - (Page y _) = Page (x-y) r
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instance Eq PageNum where
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(Page x _) == (Page y _) = x == y
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instance Ord PageNum where
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(Page a zs) <= (Page b _) = foldl (&&) True $ map (\x -> checkRule x [a, b]) zs
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instance Show PageNum where
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show (Page a _) = "Page " ++ (show a)
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addFirst :: [[a]] -> a -> [[a]]
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addFirst [] x = [[x]]
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addFirst (y:ys) x = ([x] ++ y) : ys
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split :: [Char] -> [Char] -> [[Char]]
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split _ [] = []
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split delims (x:xs)
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| elem x delims = [[]] ++ split delims xs
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| otherwise = addFirst (split delims xs) x
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toTuple :: [a] -> (a, a)
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toTuple (x:(y:ys)) = (x, y)
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splitInput :: String -> [(Integer, Integer)]
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splitInput text = map (\x -> toTuple $ map read x) $ map (filter (/="")) $ map (split ['|']) $ split ['\n'] text
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splitInput2 :: String -> [[Integer]]
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splitInput2 text = map (\x -> map read x) $ map (filter (/="")) $ map (split [',']) $ split ['\n'] text
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checkRule :: (Integer, Integer) -> [Integer] -> Bool
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checkRule _ [] = True
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checkRule (a, b) (x:xs)
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| a == x = True
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| b == x && elem a xs = False
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| b == x = True
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| otherwise = checkRule (a, b) xs
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solve1 :: [(Integer, Integer)] -> [[Integer]] -> Integer
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solve1 [] y = sum $ map (\x -> x!!(div ((length x)-1) 2)) y
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solve1 (x:xs) y = solve1 (xs) (filter (\y -> checkRule x y) y)
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solve2 :: [(Integer, Integer)] -> [[Integer]] -> PageNum
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solve2 a [] = Page 0 a
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solve2 rules (x:xs) = (getMid $ sort $ map (\a -> Page a rules) x) + (solve2 rules xs)
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getMid :: [a] -> a
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getMid xs = xs !! (div ((length xs) -1) 2)
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main :: IO()
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main = do
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fileinp <- readFile "input.txt"
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let sections = S.splitOn "\n\n" fileinp
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let parsed = splitInput (sections!!0)
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let parsed2 = splitInput2 (sections!!1)
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let solved1 = solve1 parsed parsed2
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let solved2 = (solve2 parsed parsed2) - (Page solved1 [])
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print solved1
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print solved2
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