first_come_first_served?.rb

def first_come_first_served?(take_away_orders, eat_in_orders, served_orders)

 served_orders.each do |order|
    if take_away_orders[0] === order
      # match! 
      take_away_orders.shift()
      
    elsif eat_in_orders[0] === order
      # match!
      eat_in_orders.shift()
      
    else
      # no match, not first-come first-serve
      return false
    end
  end
  
  # check for remaining extra orders
  return take_away_orders.concat(eat_in_orders).length == 0 ? true : false
end