Day4b.rb

class Board
  def self.read(stream=$<)
    new(5.times.map do
      stream.gets.split.map(&:to_i)
    end)
  end

  def initialize(grid)
    @num_grid = grid
    @mark_grid = grid.map {|row| row.map {false}}
    @by_num = {}
    grid.each_with_index do |row, i|
      row.each_with_index do |n, j|
        @by_num[n] = [i, j]
      end
    end
  end

  def play(n)
    return unless (i, j = @by_num[n])
    @mark_grid[i][j] = true
    return unless bingo?
    score(n)
  end

  def bingo?
    @mark_grid.any? {|row| row.all?} or
      @mark_grid.transpose.any? {|col| col.all?}
  end

  def score(n)
    unmarked_tot = 0
    @num_grid.each_with_index do |row, i|
      row.each_with_index do |m, j|
        unmarked_tot += m if !@mark_grid[i][j]
      end
    end
    unmarked_tot * n
  end
end

nums = gets.chomp.split(",").map(&:to_i)

boards = []
loop do
  gets or break
  boards << Board.read
end

last_score = 0
nums.each do |n|
  boards = boards.filter do |board|
    score = board.play(n)
    last_score = score if score
    !score
  end
end
print(last_score)