advent01/Main.hs

   1 -- Writeup at https://work.njae.me.uk/2021/12/01/advent-of-code-2021-day-1/
   2
   3 import Data.List
   4
   5 main :: IO ()
   6 main =
   7   do  numStrs <- readFile "data/advent01.txt"
   8       let nums = map (read @Int) $ lines numStrs
   9       print $ part1 nums
  10       print $ part2 nums
  11
  12 part1 :: [Int] -> Int
  13 part1 = countIncreasing
  14
  15 part2 :: [Int] -> Int
  16 part2 nums = countIncreasing $ map sum windows
  17   where windows = filter ((== 3) . length) $ map (take 3) $ tails nums
  18
  19 countIncreasing :: [Int] -> Int
  20 countIncreasing nums = length $ filter (uncurry (>)) $ zip (tail nums) nums