Add 2024, day 3

2024/day03/day03a

@@ -0,0 +1,9 @@
+#!/usr/bin/env ruby
+
+memory = File.read(ARGV[0]).strip
+
+res = memory.scan(/mul\(\d{1,3},\d{1,3}\)/).sum do |expr|
+  expr.scan(/\d+/).map(&:to_i).reduce(:*)
+end
+
+puts res

2024/day03/day03b

@@ -0,0 +1,24 @@
+#!/usr/bin/env ruby
+
+def evaluate(expr) = expr.scan(/\d+/).map(&:to_i).reduce(:*)
+
+ENABLE = "do()"
+DISABLE = "don't()"
+
+memory = File.read(ARGV[0]).strip
+
+total = 0
+enabled = true
+
+memory.scan(/mul\(\d{1,3},\d{1,3}\)|do\(\)|don't\(\)/).each do |expr|
+  case expr
+  when ENABLE
+    enabled = true
+  when DISABLE
+    enabled = false
+  else
+    total += evaluate(expr) if enabled
+  end
+end
+
+puts total