Prisoners Riddle

Info.md

Simulation of the Prisoners riddle as seen on Veritasium YouTube

Program.cs

using System.Security.Cryptography;

var random = RandomNumberGenerator.Create();
var boxes = Enumerable.Range(0, 100).OrderBy(_ => Randomize()).ToArray();

for (int i = 0; i < 100; i++)
{
    int opened = 0;
    int b = i;
    while (true)
    {
        ++opened;
        if (boxes[b] == i) break;
        b = boxes[b];
    }

    if (opened > 50)
    {
        Console.WriteLine($"Prisoner {i+1} failed.");
        return;
    }
}

Console.WriteLine("All prisoners succeeded.");

long Randomize()
{
    Span<byte> span = stackalloc byte[8];
    random.GetNonZeroBytes(span);
    return BitConverter.ToInt64(span);
}