From ccdfedbbb6a4fecb11ba9550a7d4df05c12d2de2 Mon Sep 17 00:00:00 2001
From: Alpha Chen <alpha@kejadlen.dev>
Date: Fri, 2 Dec 2022 21:38:11 -0800
Subject: [PATCH] [2022][ruby][3.x]

---
 2022/ruby/day_03.rb | 13 +++++++++++++
 1 file changed, 13 insertions(+)
 create mode 100644 2022/ruby/day_03.rb

diff --git a/2022/ruby/day_03.rb b/2022/ruby/day_03.rb
new file mode 100644
index 0000000..bea94f1
--- /dev/null
+++ b/2022/ruby/day_03.rb
@@ -0,0 +1,13 @@
+priorities = ((?a..?z).to_a + (?A..?Z).to_a).map.with_index { [_1, _2+1]  }.to_h
+
+# part 1
+# p ARGF.read.lines(chomp: true).map {|line|
+#   len = line.length
+#   a = line[0...len/2]
+#   b = line[len/2..]
+#   priorities.fetch((a.chars & b.chars)[0])
+# }.sum
+
+p ARGF.read.lines(chomp: true).each_slice(3).map {|chunk|
+  priorities.fetch(chunk.map(&:chars).inject(&:&)[0])
+}.sum