Day 19 part 1 Ruby solution

Author: creideiki

19-1.rb

@@ -0,0 +1,34 @@
+#!/usr/bin/env ruby
+
+class Pattern
+  def initialize(pattern, towels)
+    @pattern = pattern
+    @towels = towels.split(',').map(&:strip)
+  end
+
+  def arrange_towels(arrangement, remaining_pattern, enum)
+    enum.yield arrangement if remaining_pattern.empty?
+
+    @towels.each do |towel|
+      next unless remaining_pattern.start_with? towel
+
+      arrange_towels(arrangement + towel, remaining_pattern[towel.size..], enum)
+    end
+  end
+
+  def solve
+    solutions = Enumerator.new do |enum|
+      arrange_towels('', @pattern, enum)
+    end
+
+    solutions.peek
+    1
+  rescue StopIteration
+    0
+  end
+end
+
+lines = File.read('19.input').lines.map(&:strip)
+towels = lines[0]
+patterns = lines[2..].map { |l| Pattern.new(l, towels) }
+puts patterns.map(&:solve).sum