24 lines
598 B
Haskell
24 lines
598 B
Haskell
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#!/usr/bin/env stack
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-- stack --resolver lts-12.5 script
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module Day5A where
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import Data.Char
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import qualified Data.Foldable as F
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invertCase :: Char -> Char
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invertCase c
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| isUpper c = toLower c
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| otherwise = toUpper c
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calcLength :: String -> String -> Int
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calcLength ys (x:y:xs)
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| x == invertCase y = case length ys of
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0 -> calcLength ys xs
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_ -> calcLength (tail ys) (head ys:xs)
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| otherwise = calcLength (x:ys) (y:xs)
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calcLength ys [x] = calcLength (x:ys) []
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calcLength ys [] = length ys
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main :: IO ()
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main = interact $ show . calcLength "" . filter (/= '\n')
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