day5.hs

{-# LANGUAGE QuasiQuotes #-}

module Day5 where

import Control.Monad (void)
import Data.List (transpose)
import Data.Maybe (catMaybes)
import Text.Parsec
import Text.Parsec.String
import Text.RawString.QQ

import Util (regularParse, replaceAtIndex)

testInput1 :: String
testInput1 = [r|
    [D]    
[N] [C]    
[Z] [M] [P]
 1   2   3 

move 1 from 2 to 1
move 3 from 1 to 3
move 2 from 2 to 1
move 1 from 1 to 2
|]

type Item = Maybe Char

emptyItemParser :: Parser Item
emptyItemParser = Nothing <$ string "   "

filledItemParser :: Parser Item
filledItemParser = do
  void $ char '['
  c <- anyChar
  void $ char ']'
  return $ Just c

itemParser :: Parser Item
itemParser = emptyItemParser <|> filledItemParser

itemsParser :: Parser [Item]
itemsParser = sepBy1 itemParser $ char ' '

inputParser :: Parser [[Item]]
inputParser = do
  void endOfLine
  items <- sepBy1 itemsParser endOfLine
  endOfLine
  many1 anyChar
  endOfLine
  endOfLine
  return items