33 lines
931 B
Haskell
33 lines
931 B
Haskell
import Data.List.Split
|
|
import Data.List
|
|
import qualified Data.Set as Set
|
|
import Data.Maybe
|
|
import Linear.V2
|
|
|
|
main = do
|
|
content <- readFile "input"
|
|
let [trace1, trace2] = map gensteps $ parse content
|
|
print (day3a trace1 trace2)
|
|
print (day3b trace1 trace2)
|
|
|
|
parse :: String -> [[(Char,Int)]]
|
|
parse = map (map (\x->(head x,read $ tail x))) . map (splitOn ",") . lines
|
|
|
|
gensteps :: [(Char,Int)] -> [V2 Int]
|
|
gensteps = scanl1 (+) . concatMap (\(x,y)->replicate y $ step x)
|
|
|
|
step :: Char -> V2 Int
|
|
step x
|
|
| x=='U'=V2 0 1
|
|
| x=='R'=V2 1 0
|
|
| x=='D'=V2 0 (-1)
|
|
| x=='L'=V2 (-1) 0
|
|
|
|
day3a :: [V2 Int] -> [V2 Int] -> Int
|
|
day3a xs ys = Set.findMin $ Set.map manhattan $
|
|
(Set.fromList xs) `Set.intersection` (Set.fromList ys)
|
|
where manhattan (V2 x y) = abs x + abs y
|
|
|
|
day3b xs ys = minimum [let f = succ . fromJust . elemIndex x in f xs + f ys
|
|
| x<-Set.toList $ (Set.fromList xs) `Set.intersection` (Set.fromList ys)]
|