Day 19.1

ruby/day_19.rb

@@ -1,11 +1,14 @@
 replacements, molecule = DATA.read.chomp.split("\n\n")
-replacements = replacements.scan(/(\w+) \=> (\w+)/)
+replacements = replacements.scan(/(\w+) \=> (\w+)/).map(&:reverse).sort_by {|k,_| -k.size}
-puts replacements.flat_map {|k,v|
+
-  m = molecule.split(k, -1)
+steps = 0
-  (0...m.size-1).map {|i|
+until molecule == ?e
-    m[0..i].join(k) + v + m[i+1..-1].join(k)
+  k,v = replacements.find {|k,_| molecule.include?(k) }
-  }
+  steps += molecule.scan(/#{k}/).size
-}.uniq.size
+
+  molecule.gsub!(k, v)
+  puts "#{steps}: #{molecule}"
+end
 __END__
 Al => ThF
 Al => ThRnFAr