18 lines
573 B
Haskell
18 lines
573 B
Haskell
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import Text.Read
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import Data.Maybe
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circularSum :: [Int] -> Int
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circularSum ns = snd $ foldr (\n (prev, sum) -> (n, if n == prev then n + sum else sum)) (last ns, 0) ns
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halfwaySum :: [Int] -> Int
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halfwaySum ns =
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let ms = drop (length ns `div` 2) ns ++ take (length ns `div` 2) ns
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nms = zip ns ms
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in foldr (\(n, m) sum -> if n == m then n + sum else sum) 0 nms
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main :: IO ()
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main = do
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input <- readFile "1.txt"
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let nums = catMaybes $ map (readMaybe . (:[])) input :: [Int]
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print $ circularSum nums
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print $ halfwaySum nums
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