From 2afe23eb007d04a249e4b119d8fc72a362ec3a6c Mon Sep 17 00:00:00 2001
From: Sloane Perrault <sloane.perrault@gmail.com>
Date: Wed, 21 Sep 2022 09:19:52 -0400
Subject: [PATCH] solve: day 6, part 2 - bitwise

---
 2020/06/part2_bits.hs | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
 create mode 100755 2020/06/part2_bits.hs

diff --git a/2020/06/part2_bits.hs b/2020/06/part2_bits.hs
new file mode 100755
index 0000000..fac165f
--- /dev/null
+++ b/2020/06/part2_bits.hs
@@ -0,0 +1,17 @@
+#!/usr/bin/env runghc
+
+
+import Day6
+import Data.Bits
+import Data.Char
+
+main = interact (show . solve . lines')
+
+solve = sum . map countEveryoneYes
+
+charToBit c = bit $ ord c - ord 'a'
+
+stringToBits :: String -> Int
+stringToBits str = foldl1 (.|.) $ map charToBit str
+
+countEveryoneYes group = popCount $ foldl1 (.&.) $ map stringToBits group