{"header":{"message":"Solution for day 9","description":null,"timestamp":"2021-01-15T00:17:29Z","authors":[{"email":"jeremy.list@youdo.co.nz","name":"Jeremy List"}]},"hash":"CUOTDYHN6R6ZZAH4S2JF65QP5MQ4OZWLXB5JCL4P6RHMP2QRESXAC","authors":[],"deps":{"hashes":[["CUOTDYHN6R6ZZAH4S2JF65QP5MQ4OZWLXB5JCL4P6RHMP2QRESXAC","Solution for day 9"],["AA",null],["B527MN663VOX7PY6BCLAAU62WDPTI4JTVLNUP2UR74S4KJYKT4HQC","Solve day 1 for 2020"]],"deps":["B527MN663VOX7PY6BCLAAU62WDPTI4JTVLNUP2UR74S4KJYKT4HQC"],"known":[]},"hunks":[{"FileAdd":{"meta":{"basename":"day9.hs","metadata":0},"context":[{"change":2,"pos":17}],"contents":[{"Add":"import Control.Monad"},{"Add":"import Data.List"},{"Add":"import qualified Data.Set as S"},{"Add":"import System.Environment"},{"Add":""},{"Add":"stretches :: Int -> [a] -> [([a],a)]"},{"Add":"stretches n l = let"},{"Add":" (i,z) = splitAt n l"},{"Add":" go _ [] = []"},{"Add":" go p (a:r) = (p,a) : go (drop 1 p ++ [a]) r"},{"Add":" in go i z"},{"Add":""},{"Add":"valid p n = not $ null $ do"},{"Add":" (a:r) <- tails $ sort $ filter (< n) p"},{"Add":" let t = n - a"},{"Add":" (_,ge) <- [break (>= t) r]"},{"Add":" (_:_) <- [takeWhile (== t) ge]"},{"Add":" return ()"},{"Add":""},{"Add":"part1 :: (Num n, Ord n) => [n] -> n"},{"Add":"part1 = snd . head . filter (not . uncurry valid) . stretches 25"},{"Add":""},{"Add":"stretchesWithSum :: (Num a, Ord a) => a -> [a] -> [[a]]"},{"Add":"stretchesWithSum t = go 0 [] where"},{"Add":" go es e r = case es `compare` t of"},{"Add":" LT -> case r of"},{"Add":" (h:r') -> go (es + h) (e ++ [h]) r'"},{"Add":" [] -> []"},{"Add":" EQ -> e : let"},{"Add":" (d:r') = e"},{"Add":" in go (es - d) r' r"},{"Add":" GT -> let"},{"Add":" (d:r') = e"},{"Add":" in go (es - d) r' r"},{"Add":""},{"Add":"part2 :: (Num n, Ord n) => [n] -> n -> n"},{"Add":"part2 l e = head $ do"},{"Add":" l'@(_:_:_) <- stretchesWithSum e l"},{"Add":" Just (MinMax a h) <- pure $ foldMap (Just . minMax) l'"},{"Add":" return (a + h)"},{"Add":""},{"Add":"data MinMax a = MinMax a a"},{"Add":""},{"Add":"instance Ord a => Semigroup (MinMax a) where"},{"Add":" MinMax l1 h1 <> MinMax l2 h2 = MinMax (min l1 l2) (max h1 h2)"},{"Add":""},{"Add":"minMax :: a -> MinMax a"},{"Add":"minMax = join MinMax"},{"Add":""},{"Add":"main :: IO ()"},{"Add":"main = do"},{"Add":" [fn] <- getArgs"},{"Add":" d <- (map (read :: String -> Integer) . words) <$> readFile fn"},{"Add":" let p1 = part1 d"},{"Add":" print p1"},{"Add":" print $ part2 d p1"},{"Add":""}]}}],"owner":"quickdudley","repo":"adventofcode","token":"Cx7AvLTP9b3rdGluLIIvrEpTzxFkG5rd7MOHUVjfuDo=","login":null}

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