From b07bc495bb62ccb21dfae7db5a6ac3c0e7381ab8 Mon Sep 17 00:00:00 2001
From: Jonathan Chan <jonathanhwchan@gmail.com>
Date: Sun, 2 Dec 2018 09:28:02 -0800
Subject: [PATCH] Day 02 - (\) deletes the first occurrence, so back to using
 zip + filter.

---
 src/Day02.hs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/Day02.hs b/src/Day02.hs
index 62cd322..300cf0e 100644
--- a/src/Day02.hs
+++ b/src/Day02.hs
@@ -7,7 +7,8 @@ part1 strs = (length . filter (count 2) $ strs) * (length . filter (count 3) $ s
     where count n = any (== n) . map length . group . sort
 
 part2 :: [String] -> String
-part2 strs = head [ls `intersect` rs | ls <- strs, rs <- strs, length (ls \\ rs) == 1]
+part2 strs = head [xs `intersect` ys | xs <- strs, ys <- strs, dist xs ys == 1]
+    where dist = (length .) . (filter id .) . zipWith (/=)
 
 main :: IO ()
 main = do