epsilon_greedy.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace epsilon_greedy
{
    class Program
    {
        /*
         * SAMPLE OUTPUT: 
         *
         * Program started...
         * Finished running in 16134 ms
         * Orange was clicked 1586780 times and seen 8814219 times. Click rate is 18.00%
         * Blue was clicked 30125 times and seen 603095 times. Click rate is 5.00%
         * Green was clicked 58214 times and seen 582689 times. Click rate is 9.99%
         * Enter any key to close the program...
         */

        static void Main(string[] args)
        {
            // We'll do this 1 million times
            int iterations = 10000000;

            // We declare our banners
            DemoBanners orange = new DemoBanners { Name = "Orange", TimesClicked = 1, TimesSeen = 1, ClickOdds = 18 };
            DemoBanners blue   = new DemoBanners { Name = "Blue",   TimesClicked = 1, TimesSeen = 1, ClickOdds = 5  };
            DemoBanners green  = new DemoBanners { Name = "Green",  TimesClicked = 1, TimesSeen = 1, ClickOdds = 10 };

            Stopwatch stopWatch = new Stopwatch();

            Console.WriteLine("Program started...");

            stopWatch.Start();

            List<DemoBanners> banners = new List<DemoBanners> { orange, blue, green };

            Random random = new Random();

            for (int i = 0; i < iterations; i++)
            {
                DemoBanners selected = DemoBanners.Choose(banners);

                selected.TimesSeen++;

                if (random.Next(1, 101) <= selected.ClickOdds)
                {
                    selected.TimesClicked++;
                }
            }

            stopWatch.Stop();

            Console.WriteLine("Finished running in {0} ms", stopWatch.ElapsedMilliseconds);

            foreach (DemoBanners b in banners)
            {
                Console.WriteLine("{0} was clicked {1} times and seen {2} times. Click rate is {3:0.00}%", b.Name, b.TimesClicked, b.TimesSeen, 100m * Decimal.Divide(b.TimesClicked, b.TimesSeen));
            }

            Console.WriteLine("Enter any key to close the program...");

            Console.ReadKey();
        }
    }

    class DemoBanners
    {
        public string Name { get; set; }
        public int TimesClicked { get; set; }
        public int TimesSeen { get; set; }
        // The odds someone will click on our stuff, % based
        public int ClickOdds { get; set; }

        public static DemoBanners Choose(List<DemoBanners> banners)
        {
            Random random = new Random();
            // 10% of the time we explore!
            if (random.Next(1, 101) <= 10)
            {
                // We return a random item
                return banners[random.Next(0, banners.Count)];
            }
            else
            {
                // We return the item with the greatest odds,
                // if more than one has the same odds we return the first one we find
                decimal maximum = banners.Max(x => Decimal.Divide(x.TimesClicked, x.TimesSeen));

                return banners.First(r => Decimal.Divide(r.TimesClicked, r.TimesSeen) == maximum);
            }
        }
    }
}