Day 4

[advent-of-code-17.git] / src / advent04 / advent04.hs

diff --git a/src/advent04/advent04.hs b/src/advent04/advent04.hs
new file mode 100644 (file)
index 0000000..b8ae85c
--- /dev/null
+++ b/src/advent04/advent04.hs
@@ -0,0 +1,28 @@
+import Data.List (sort)
+import Data.List.Split (splitOn)
+import qualified Data.Map.Strict as M
+
+main :: IO ()
+main = do 
+        text <- readFile "data/advent04.txt"
+        let passphrases = map parseLine $ lines text
+        print $ part1 passphrases
+        print $ part2 passphrases
+
+part1 :: [[String]] -> Int
+part1 = length . filter (not . containsDuplicates) 
+
+part2 :: [[String]] -> Int
+part2 = length . filter (not . containsAnagrams) 
+
+parseLine :: String -> [String]
+parseLine = filter (not . null) . splitOn " "    
+
+frequency :: (Ord a) => [a] -> M.Map a Int 
+frequency xs = M.fromListWith (+) [(x, 1) | x <- xs]
+
+containsDuplicates :: [String] -> Bool
+containsDuplicates = (not . M.null) . M.filter (> 1) . frequency
+
+containsAnagrams :: [String] -> Bool
+containsAnagrams = containsDuplicates . (map sort)