class Combination
  attr_reader :steps
  def initialize(steps)
    @steps = steps
  end

  def self.for(string)
    new string.split("\n").map{ |line| Step.for line }
  end

  def zero_count
    safe = Safe.new
    zc = 0
    steps.each do |step|
      safe.apply_step step
      zc += 1 if safe.count.zero?
    end
    zc
  end

  def zero_click_count
    safe = Safe.new
    steps.each do |step|
      safe.apply_step step
    end
    safe.zero_clicks
  end

  class Step
    attr_reader :dir, :count
    def initialize(dir, count)
      @dir = dir
      @count = dir == "R" ? count : -count
    end

    def self.for(string)
      new string[0], string[1..].to_i
    end
  end

  class Safe
    attr_reader :count
    attr_reader :zero_clicks
    def initialize
      @count = 50
      @zero_clicks = 0
    end

    def apply_step(step)
      if step.dir == "R"
        0.upto(step.count - 1) do
          @count += 1
          @count = @count % 100
          @zero_clicks += 1 if @count.zero?
        end
      else
        0.upto(-step.count - 1) do
          @count -= 1
          @count = @count % 100
          @zero_clicks += 1 if @count.zero?
        end
      end
    end
  end
end