You run an e-commerce website and want to record the last N order ids in a log. Implement a data structure to accomplish this, with the following API: record(order_id): adds the order_id to the log get_last(i): gets the ith last element from the log. i is guaranteed to be smaller than or equal to N. You should be as efficient with time and space…

daily-coding-problem-16.rb

#!/usr/bin/env ruby

class Log 
    def initialize(log=["1","2","3","4"])
        @log = log
    end 
    def size 
        return @log.length 
    end
    def record(order_id)
        if order_id.respond_to?("each")
            order_id.each do |o|
                @log << o
            end
        else 
            @log << order_id
        end
    end 
    def get_last(i)
        if i>size() || i<1
            puts "Index Invalid!"
            return 
        end 
        return @log.slice(size()-i,size())
    end
end

l = Log.new()
l.record("5")
puts l.get_last(2)