bowling_h.rb

def score(pins)
  frames = pins.join(',').scan(/(\d+),?(\d+)?/).map{|e| e.map{|i| i.to_i}}
  ss = frames.map{|s1, s2| s1 == 10 ? :strike : (s1 + s2 == 10 ? :spare : nil)}
  sum = frames.size > 10 ? frames.pop[0] : 0
  frames.zip(ss.unshift(nil)).zip(ss.unshift(nil)).map{|e1, e2| [e1[0], [e1[1], e2]]}.each do |score, hist|
    sum += score[0] if hist[0] == :strike and hist[1] == :strike
    case hist[0]
    when :strike
      sum += score[0] + score[1]
    when :spare
      sum += score[0]
    end
    sum += score[0] + score[1]
  end
  sum
end

def bowl(n)
  @pins ||= []
  @pins << n
  score(@pins)
end

pins = [1, 4, 2, 8, 5, 0, 10, 0, 0, 4, 5, 5, 2, 0, 6, 1, 10, 0, 10, 5, 5]
pins.each do |n|
  puts sprintf("%2d %d\n", n, bowl(n))
end