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advent-of-code/2020/01/part1.hs
2022-09-21 09:19:52 -04:00

24 lines
458 B
Haskell
Executable file

#!/usr/bin/env runghc
import Data.List
import Data.Maybe
main :: IO ()
main =
do
input <- getInput
let answer = uncurry (*) $ fromJust $ find isSolutionPair $ pairs input
putStrLn $ show answer
getInput :: IO [Int]
getInput = fmap (map read . lines) getContents
pairs :: [a] -> [(a, a)]
pairs [] = []
pairs [_] = []
pairs (x:xs) = [(x, y) | y <- xs] ++ pairs xs
isSolutionPair :: (Int, Int) -> Bool
isSolutionPair (a, b) = a + b == 2020