33 lines
973 B
Haskell
33 lines
973 B
Haskell
{-# LANGUAGE LambdaCase #-}
|
|
module Main where
|
|
|
|
import Data.Functor
|
|
import Data.Char
|
|
import Data.Matrix hiding (trace)
|
|
import Data.List
|
|
|
|
parse :: String -> Matrix Int
|
|
parse = fromLists . ((digitToInt <$>) <$>) . lines
|
|
|
|
getAllDigit :: Int -> Matrix Int -> [(Int,Int)]
|
|
getAllDigit c s = zip [1..] (toLists s) >>= \(y,l) -> zip [1..] l >>= \(x,c') ->
|
|
if c == c' then pure (y,x) else mempty
|
|
|
|
getAbove :: (Int,Int) -> Matrix Int -> [(Int,Int)]
|
|
getAbove (y,x) s = let target = getElem y x s + 1 in
|
|
filter ((Just target ==) . flip (uncurry safeGet) s) [(y-1,x),(y+1,x),(y,x-1),(y,x+1)]
|
|
|
|
travel :: (Int,Int) -> Matrix Int -> [(Int,Int)]
|
|
travel p s = let curr = uncurry getElem p s in
|
|
if curr == 9 then [p] else getAbove p s >>= (`travel` s)
|
|
|
|
solve1 :: Matrix Int -> Int
|
|
solve1 s = length . concatMap (nub . (`travel` s)) $ getAllDigit 0 s
|
|
|
|
solve2 = undefined
|
|
|
|
main :: IO ()
|
|
main = readFile "inputs/10" <&> parse >>= \i ->
|
|
print (solve1 i)
|
|
-- >> print (solve2 i)
|