aoc2022day4.hs

import qualified Data.Text as T

main = do
  input <- readFile "input.txt"
  print $ countpredranges oneissubset input
  print $ countpredranges theyoverlap input

type Range = (Int, Int)

countpredranges :: (Range -> Range -> Bool) -> String -> Int
countpredranges predicate = 
  length . (filter (uncurry predicate)) . (fmap parseline) . lines

parseline :: String -> (Range, Range)
parseline line = case nums of {
    ((w:x:[]) : (y:z:[]) : []) -> ((w, x), (y, z));
    _ -> undefined
  } where 
    listoflists = fmap (split "-") $ split "," line
    nums = fmap (fmap read) listoflists 

oneissubset :: Range -> Range -> Bool
oneissubset a b = (acontainsb a b) || (acontainsb b a)

acontainsb :: Range -> Range -> Bool
acontainsb (w, x) (y, z) = 
  (y >= w)
  && (y <= x)
  && (z >= w)
  && (z <= x)

theyoverlap :: Range -> Range -> Bool
theyoverlap (w, x) (y, z) = 
  (y >= w) && (y <= x) 
  || (z >= w) && (z <= x) 
  || (w >= y) && (w <= z)
  || (x >= y) && (x <= z)

split :: String -> String -> [String]
split delim str = fmap T.unpack $ T.splitOn (T.pack delim) (T.pack str)