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CSharp · Console

/Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
					
	public class Program
    {
        const string alphabet = "qwertyuiopasdfghjklzxcvbnm !QWERTYUIOPASDFGHJKLZXCVBNM";
        static Random rnd = new Random();
        const string target = "Hello World!";
        const int mutationChance = 20;

        public static void Main(string[] args)
        {
            List<Entity> entities = GenEntities(500);
            uint gen = 0;

            double bestFitness = -1;
            while (entities.Select(x => x.fitness).Max() != 1)
            {
                gen++;
                // Set fitness
                entities.ForEach(x => x.setFitness(target));
                // Order by fitness
                entities = entities.OrderBy(x => x.fitness).ToList();
                // Kill worst half
                const int kill = 250;
                entities.RemoveRange(0, kill);
                // Gen them again
                entities = Reproduce(entities, kill);

                bestFitness = entities.Select(x => x.fitness).Max();
                Console.Write(bestFitness.ToString().PadRight(25));
                Console.WriteLine(entities.Where(x => x.fitness == bestFitness).First().output);
            }

            Console.WriteLine("Generation: " + gen);
            Entity ThatOne = entities.Where(x => x.fitness == entities.Select(a => a.fitness).Max()).First();
            Console.WriteLine("Best Entity: {0}, {1}", ThatOne.output, ThatOne.fitness);
        }

        static List<Entity> GenEntities(int n = 1000)
        {
            List<Entity> list = new List<Entity>();

            for (int i = 0; i < n; i++)
            {
                string s = "";
                for (int j = 0; j < target.Length; j++)
                {
                    s += alphabet[rnd.Next(alphabet.Length)];
                }
                list.Add(new Entity(s, 0));
            }

            return list;
        }

        static List<Entity> Reproduce(List<Entity> entities, int reproduceN)
        {
            List<Entity> newEntities = new List<Entity>();
            for (int i = 0; i < reproduceN; i++)
            {
                // Choose first one
                Entity first = /*entities[rnd.Next(entities.Count)]*/ entities.Last();
                // Choose second one
                Entity second = entities[rnd.Next(entities.Count)];

                // Choose genetic line
                int line = rnd.Next(1, target.Length - 1);
                string output = "";
                // Combine entity info
                for (int j = 0; j < line; j++)
                {
                    if (rnd.Next(101) < mutationChance)
                        output += alphabet[rnd.Next(alphabet.Length)];
                    else
                        output += first.output[j];
                }
                for (int j = line; j < target.Length; j++)
                {
                    if (rnd.Next(101) < mutationChance)
                        output += alphabet[rnd.Next(alphabet.Length)];
                    else
                        output += second.output[j];
                }
                newEntities.Add(new Entity(output, 0));
            }
            entities.AddRange(newEntities);
            return entities;
        }
    }

    class Entity
    {
        public string output = "";
        public double fitness = 0;

        public Entity(string output, double fitness)
        {
            this.output = output;
            this.fitness = fitness;
        }

        public void setFitness(string target)
        {
            int right = 0;
            for (int i = 0; i < target.Length; i++)
            {
                if (target[i] == output[i])
                    right++;
            }
            fitness = right / (double)target.Length;
        }
    }