41 lines
1 KiB
Haskell
41 lines
1 KiB
Haskell
|
module Day2 where
|
||
|
|
|
||
|
|
import AoC
|
||
|
|
|
||
|
|
import Data.Char
|
||
|
|
import Data.Maybe
|
||
|
|
import Text.ParserCombinators.ReadP
|
||
|
|
import Text.Read.Lex
|
||
|
|
|
||
|
|
data Line = Line
|
||
|
|
{ num1 :: Int
|
||
|
|
, num2 :: Int
|
||
|
|
, letter :: Char
|
||
|
|
, password :: String
|
||
|
|
}
|
||
|
|
|
||
|
|
instance Show Line where
|
||
|
|
show (Line num1 num2 letter password) = show num1 ++ "-" ++ show num2 ++ " " ++ [letter] ++ ": " ++ password
|
||
|
|
|
||
|
|
parseLine :: ReadP Line
|
||
|
|
parseLine = do
|
||
|
|
num1 <- readDecP
|
||
|
|
string "-"
|
||
|
|
num2 <- readDecP
|
||
|
|
string " "
|
||
|
|
letter <- get
|
||
|
|
string ": "
|
||
|
|
password <- munch1 $ const True
|
||
|
|
eof
|
||
|
|
return (Line num1 num2 letter password)
|
||
|
|
|
||
|
|
valid_1 :: Line -> Bool
|
||
|
|
valid_1 (Line min max letter password) = within min max $ length $ filter (== letter) password
|
||
|
|
where within x y z = x <= z && z <= y
|
||
|
|
|
||
|
|
valid_2 :: Line -> Bool
|
||
|
|
valid_2 (Line pos1 pos2 letter password) = (matchesAt pos1) /= (matchesAt pos2)
|
||
|
|
where matchesAt pos = password !! (pos-1) == letter
|
||
|
|
|
||
|
|
main = runAoC (map (fromJust . oneCompleteResult parseLine) . lines) (length . filter valid_1) (length . filter valid_2)
|