48 lines
1.3 KiB
Haskell
48 lines
1.3 KiB
Haskell
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module Day4.Main where
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import System.IO
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import Data.List.Split
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main :: IO ()
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main = do
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putStrLn "Day 4"
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handle <- openFile "app/Day4/input" ReadMode
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contents <- hGetContents handle
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let r1 = part1 contents
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putStrLn $ "part 1: " ++ show r1
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let r2 = part2 contents
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putStrLn $ "part 2: " ++ show r2
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listToPair :: [a] -> (a, a)
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listToPair l = (l !! 0, l !! 1)
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type Start = Int
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type End = Int
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type Section = (Start, End)
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parseData :: String -> [(Section, Section)]
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parseData contents = transformOuter
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where
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pairs = map (splitOn ",") (lines contents)
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ranges = (map . map) (splitOn "-") pairs
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toNumbers = (map . map . map) (read :: String -> Int) ranges
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transformInner = (map . map) listToPair toNumbers
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transformOuter = map listToPair transformInner
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contained :: Section -> Section -> Bool
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contained (as, ae) (bs, be) = as <= bs && ae >= be || bs <= as && be >= ae
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overlap :: Section -> Section -> Bool
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overlap (as, ae) (bs, be) = bs <= as && be >= as ||
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bs <= ae && be >= ae ||
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as <= bs && ae >= bs ||
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as <= be && ae >= be
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part1, part2 :: String -> Int
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part1 contents = length $ filter (uncurry contained) $ parseData contents
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part2 contents = length $ filter (uncurry overlap) $ parseData contents
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