Hash Collisions

using System;
using System.Collections;

namespace ConsoleApplication1
{
    public class Program
    {
        static void Main()
        {
            var positive = new BitArray(int.MaxValue);
            var negative = new BitArray(int.MaxValue);
            var collisionFound = false;
            var iterations = 0;

            while (!collisionFound)
            {
                iterations++;
                var guid = Guid.NewGuid();
                var hashcode = guid.GetHashCode();
                var which = hashcode >= 0 ? positive : negative;

                hashcode = Math.Abs(hashcode);

                if (which[hashcode])
                {
                    collisionFound = true;
                }

                which[hashcode] = true;
            }

            Console.WriteLine("Collision found in {0} iterations", iterations);
        }
    }
}