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module Main where
import Utils
import Data.List (inits, tails, find, sort)
import Data.Bifunctor
parseLine :: String -> Int
parseLine = read
doCheck :: [Int] -> Int -> Bool
doCheck preamble target = target `elem` p
where p = [x + y | x <- preamble, y <- preamble, x /= y]
checkAll :: [[Int]] -> [Int] -> [(Int, Bool)]
checkAll = zipWith (\p t -> (t, doCheck p t))
findWeakness :: [[Int]] -> Int -> Int
findWeakness subs target = minimum t + maximum t
where Just t = find ((== target) . sum) subs
main :: IO ()
main = do
n <- map parseLine . lines <$> readFile "input/09"
let preambleLen = 25
Just (target, _) = find (not . snd) $ checkAll (windows preambleLen n) (drop preambleLen n)
print target
print $ findWeakness (sublists n) target
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