[2023][ruby][2.*]

2023/ruby/day_02.rb

@@ -0,0 +1,39 @@
+input = ARGF.read
+
+def cubes(input)
+  input
+    .scan(/(\d+) (\w+)/)
+    .to_h(&:reverse)
+    .transform_values(&:to_i)
+end
+
+bag = cubes("12 red cubes, 13 green cubes, and 14 blue cubes")
+
+Game = Data.define(:id, :reveals) do
+  def possible?(bag)
+    reveals.all? {|reveal|
+      bag.all? {|color, n| n >= reveal.fetch(color, 0) }
+    }
+  end
+end
+
+games = input
+  .scan(/^Game (\d+): ((?~\n))/)
+  .map {|id, reveals|
+    Game.new(
+      id.to_i,
+      reveals.split(?;).map { cubes(_1) }
+    )
+  }
+
+# part one
+p games.select { _1.possible?(bag) }.sum(&:id)
+
+# part two
+p games
+  .map {|game|
+    game.reveals.inject {|bag, reveal|
+      bag.merge(reveal) { [_2, _3].max }
+    }
+  }
+  .sum {|bag| bag.values.inject(:*) }