DataStructure

.rb

class DataStructure
  def initialize
    @data = {}
    @default = nil
  end

  def set(index, value)
    @data[index] = value
  end
  
  def get(index)
    value = @data[index]
    value ? value : @default
  end

  def set_all(value)
    @data = {}
    @default = value
  end
end