From 75fa851ff5bb054d05a86c0a11b2ae085dda54b0 Mon Sep 17 00:00:00 2001
From: Joscha <joscha@plugh.de>
Date: Sun, 6 Dec 2020 10:33:10 +0000
Subject: [PATCH] [hs] Solve 2020_06

---
 hs/src/Aoc/Y2020.hs     |  2 ++
 hs/src/Aoc/Y2020/D06.hs | 25 +++++++++++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 hs/src/Aoc/Y2020/D06.hs

diff --git a/hs/src/Aoc/Y2020.hs b/hs/src/Aoc/Y2020.hs
index 40ed4de..60fa930 100644
--- a/hs/src/Aoc/Y2020.hs
+++ b/hs/src/Aoc/Y2020.hs
@@ -8,6 +8,7 @@ import qualified Aoc.Y2020.D02 as D02
 import qualified Aoc.Y2020.D03 as D03
 import qualified Aoc.Y2020.D04 as D04
 import qualified Aoc.Y2020.D05 as D05
+import qualified Aoc.Y2020.D06 as D06
 
 days :: [Day]
 days =
@@ -16,4 +17,5 @@ days =
   , D03.day
   , D04.day
   , D05.day
+  , D06.day
   ]
diff --git a/hs/src/Aoc/Y2020/D06.hs b/hs/src/Aoc/Y2020/D06.hs
new file mode 100644
index 0000000..73dad68
--- /dev/null
+++ b/hs/src/Aoc/Y2020/D06.hs
@@ -0,0 +1,25 @@
+module Aoc.Y2020.D06
+  ( day
+  ) where
+
+import qualified Data.Set  as Set
+
+import           Aoc.Day
+import           Aoc.Parse
+
+type Group = [String]
+
+parser :: Parser [Group]
+parser = sepBy (endBy1 (some lowerChar) newline) newline
+
+solver :: [Group] -> IO ()
+solver groups = do
+  putStrLn ">> Part 1"
+  print $ sum $ map (Set.size . foldr1 Set.union . map Set.fromList) groups
+
+  putStrLn ""
+  putStrLn ">> Part 2"
+  print $ sum $ map (Set.size . foldr1 Set.intersection . map Set.fromList) groups
+
+day :: Day
+day = dayParse "2020_06" parser solver