秋意正浓，我又开始怀念那个13了，于是找到了两道题号13开头的leetcode题，并ac了它们，突然觉得美滋滋的。
1396. 设计地铁系统

class UndergroundSystem
    def initialize()
      @h = {}
      @hid = {}
    end


=begin
    :type id: Integer
    :type station_name: String
    :type t: Integer
    :rtype: Void
=end
    def check_in(id, station_name, t)
      unless @hid.has_key?(id)
        @hid[id] = [[station_name,t]]
      else
        @hid[id].push([station_name,t])
      end
    end


=begin
    :type id: Integer
    :type station_name: String
    :type t: Integer
    :rtype: Void
=end
    def check_out(id, station_name, t)
      @hid[id][-1].push(station_name)
      @hid[id][-1].push(t)
      unless @h.has_key?(@hid[id][-1][0]+"_"+@hid[id][-1][2])
        @h[@hid[id][-1][0]+"_"+@hid[id][-1][2]] = []
        @h[@hid[id][-1][0]+"_"+@hid[id][-1][2]].push(@hid[id][-1][3]-@hid[id][-1][1])
      else
        @h[@hid[id][-1][0]+"_"+@hid[id][-1][2]].push(@hid[id][-1][3]-@hid[id][-1][1])
      end
    end


=begin
    :type start_station: String
    :type end_station: String
    :rtype: Float
=end
    def get_average_time(start_station, end_station)
      @h[start_station+"_"+end_station].sum/@h[start_station+"_"+end_station].length.to_f
    end


end

# Your UndergroundSystem object will be instantiated and called as such:
# obj = UndergroundSystem.new()
# obj.check_in(id, station_name, t)
# obj.check_out(id, station_name, t)
# param_3 = obj.get_average_time(start_station, end_station)

1352. 最后 K 个数的乘积

class ProductOfNumbers
    def initialize()
      @num = []
      @h = {}
    end


=begin
    :type num: Integer
    :rtype: Void
=end
    def add(num)
      if @num.length == 0 && num > 0
        @num.push(num)
      elsif @num.length > 0 && num > 0 && @num[-1] != 0
        @num.push(@num[-1]*num)
      elsif @num.length == 0 && num == 0
        @num.push(num)
        @h[0] = 0
      elsif @num.length > 0 && num == 0
        @num.push(0)
        @h[0] = @num.length - 1
      elsif @num.length > 0 && num > 0 && @num[-1] == 0
        @num.push(num)
      end
    end


=begin
    :type k: Integer
    :rtype: Integer
=end
    def get_product(k)
      if @num[-k] == 0
        return 0
      else
        if @h.length == 0 && k != @num.length
          return @num[-1]/@num[@num.length-k-1]
        elsif @h.length == 0 && k == @num.length
          return @num[-1]
        else
          if @h[0] < @num.length - k
            if @num.length - k - 1 == @h[0]
              return @num[-1]
            else
              return @num[-1]/@num[@num.length-k-1]
            end
          else
            return 0
          end
        end
      end
    end


end

# Your ProductOfNumbers object will be instantiated and called as such:
# obj = ProductOfNumbers.new()
# obj.add(num)
# param_2 = obj.get_product(k)

最后就让13深藏于心吧