From c1cae2ec6d4c6493d08998d5ad7158fc42192547 Mon Sep 17 00:00:00 2001
From: Alpha Chen <alpha@kejadlen.dev>
Date: Thu, 5 Dec 2024 07:34:45 -0800
Subject: [PATCH] [2024][ruby][5.x]

---
 2024/ruby/day_05.rb | 44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 2024/ruby/day_05.rb

diff --git a/2024/ruby/day_05.rb b/2024/ruby/day_05.rb
new file mode 100644
index 0000000..d01a96f
--- /dev/null
+++ b/2024/ruby/day_05.rb
@@ -0,0 +1,44 @@
+rules, updates = DATA.read.split("\n\n")
+
+rules = rules.scan(/(\d+)\|(\d+)/).map { _1.map(&:to_i) }
+updates = updates.lines.map { _1.split(?,).map(&:to_i) }
+
+correct, incorrect = updates.partition {|pages|
+  pages.each_cons(2).all? { rules.include?(_1) }
+}
+
+pp correct.sum { _1[_1.length/2] }
+
+pp incorrect.map {|pages|
+  pages.sort {|a,b| rules.include?([a,b]) ? -1 : 1 }
+}.sum { _1[_1.length/2] }
+
+__END__
+47|53
+97|13
+97|61
+97|47
+75|29
+61|13
+75|53
+29|13
+97|29
+53|29
+61|53
+97|53
+61|29
+47|13
+75|47
+97|75
+47|61
+75|61
+47|29
+75|13
+53|13
+
+75,47,61,53,29
+97,61,53,29,13
+75,29,13
+75,97,47,61,53
+61,13,29
+97,13,75,29,47