advent03.hs

   1 import Data.List
   2 import Data.List.Split
   3
   4 type Triple = [Integer]
   5
   6 main :: IO ()
   7 main = do
   8         instrText <- readFile "advent03.txt"
   9         let triangles = map (parseLine) $ lines instrText
  10         part1 triangles
  11         part2 triangles
  12
  13
  14 part1 :: [Triple] -> IO ()
  15 part1 triangles = do
  16     print $ length $ filter (validTriangle) triangles
  17
  18 part2 :: [Triple] -> IO ()
  19 part2 triangles = do
  20     print $ length $ filter (validTriangle) $ byColumns triangles
  21
  22
  23 parseLine :: String -> Triple
  24 parseLine = map (read) . filter (not . null) . splitOn " "
  25
  26 validTriangle triple = sortedTriple!!0 + sortedTriple!!1 > sortedTriple!!2
  27     where sortedTriple = sort triple
  28
  29 byColumns triangles = chunksOf 3 $ concat $ transpose triangles