32 lines
957 B
Haskell
32 lines
957 B
Haskell
|
module Main (main) where
|
||
|
|
import Control.Monad (when)
|
||
|
|
import Data.List (foldl')
|
||
|
|
import System.Exit (die)
|
||
|
|
|
||
|
|
exampleExpectedOutput = 127
|
||
|
|
|
||
|
|
parseInput :: String -> IO [Int]
|
||
|
|
parseInput filename = do
|
||
|
|
input <- readFile filename
|
||
|
|
return $ map read $ lines input
|
||
|
|
|
||
|
|
validate :: [Int] -> Int -> Bool
|
||
|
|
validate list n = processInput list
|
||
|
|
where
|
||
|
|
processInput :: [Int] -> Bool
|
||
|
|
processInput (_:[]) = False
|
||
|
|
processInput (x:xs) = (foldl' (\acc i -> acc || (x + i == n && x /= i)) False xs) || processInput xs
|
||
|
|
|
||
|
|
compute :: Int -> [Int] -> Int
|
||
|
|
compute len list
|
||
|
|
| validate (take len list) (list !! len) = compute len $ tail list
|
||
|
|
| otherwise = list !! len
|
||
|
|
|
||
|
|
main :: IO ()
|
||
|
|
main = do
|
||
|
|
example <- parseInput "example"
|
||
|
|
let exampleOutput = compute 5 example
|
||
|
|
when (exampleOutput /= exampleExpectedOutput) (die $ "example failed: got " ++ show exampleOutput ++ " instead of " ++ show exampleExpectedOutput)
|
||
|
|
input <- parseInput "input"
|
||
|
|
print $ compute 25 input
|