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module Main (main) where
import Control.Monad (when)
import Data.List (group, sort)
import System.Exit (die)
exampleExpectedOutput = 8
exampleExpectedOutput2 = 19208
parseInput :: String -> IO [Int]
parseInput filename = do
input <- readFile filename
return $ map read $ lines input
compute :: [Int] -> Int
compute jolts = product $ map (([1, 1, 2, 4, 7, 13, 24] !!) . length) $ filter ((==) 1 . head) $ group $ zipWith (-) s (0 : s) --snd . head $ foldl compute' [(0, 1)] $ sort jolts
where
s = sort jolts
--compute' (prev, n) x =
--compute' (x:xs) = (length $ takeWhile (\i -> i <= x + 3) xs) * compute' xs
main :: IO ()
main = do
example <- parseInput "example"
let s = sort example
print s
print $ zipWith (-) s (0 : s)
print $ group $ zipWith (-) s (0 : s)
print $ filter ((==) 1 . head) $ group $ zipWith (-) s (0 : s)
print $ map length $ filter ((==) 1 . head) $ group $ zipWith (-) s (0 : s)
let exampleOutput = compute example
when (exampleOutput /= exampleExpectedOutput) (die $ "example failed: got " ++ show exampleOutput ++ " instead of " ++ show exampleExpectedOutput)
example2 <- parseInput "example2"
let exampleOutput2 = compute example2
when (exampleOutput2 /= exampleExpectedOutput2) (die $ "example2 failed: got " ++ show exampleOutput2 ++ " instead of " ++ show exampleExpectedOutput2)
input <- parseInput "input"
print $ compute input
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