Initial commit

2017/13/day13.hs

@@ -0,0 +1,31 @@
+#!/usr/bin/env stack
+-- stack --resolver lts-9.18 script --package ghc --package text
+
+{-# LANGUAGE OverloadedStrings #-}
+import Data.Text (Text)
+import qualified Data.Text as T
+import Util (filterByList)
+import Data.List
+
+caught :: [Int] -> [Int] -> [Bool]
+caught = zipWith (\d k -> d `rem` (2*(k-1)) == 0)
+
+severity :: [Int] -> [Int] -> [Bool] -> Int
+severity depths ranges catches =
+  sum $ zipWith (*) depths' ranges'
+  where depths' = filterByList catches depths
+        ranges' = filterByList catches ranges
+
+findDelay :: Int -> [Int] -> [Int] -> Int
+findDelay dt depths ranges =
+  if not . or $ caught (map (+dt) depths) ranges then
+    dt
+  else findDelay (dt+1) depths ranges
+
+main :: IO ()
+main = do
+  contents <- T.lines . T.pack <$> getContents
+  let depths:ranges:_ = transpose $ map (read . T.unpack) . T.splitOn ": " <$> contents
+  putStrLn . show $ severity depths ranges (caught depths ranges)
+  putStrLn . show $ findDelay 0 depths ranges
+