--- Day 4: Secure Container ---

Haskell

Hoping that this still qualifies as short.

module Day04 where

import           Data.List (group)
import           Data.Char (digitToInt)

digits :: Int -> [Int]
digits = map digitToInt . show

cond3 :: (Int -> Int -> Bool) -> Int -> Bool
cond3 cmp = any (cmp 2 . length) . group . digits

cond4 :: Int -> Bool
cond4 xs = let ds = digits xs in and $ zipWith (<=) ds (tail ds)

part1 = length [x | x <- [347312..805915], cond3 (<=) x, cond4 x] 
part2 = length [x | x <- [347312..805915], cond3 (==) x, cond4 x] 

main :: IO ()
main = do
  print part1
  print part2