rsgc 1.1.0

using System;
using System.Threading.Tasks;

class BinaryTrees
{
    class TreeNode
    {
        readonly TreeNode left, right;

        internal TreeNode(int d)
        {
            if(d != 0)
            {
                left = new TreeNode(d - 1);
                right = new TreeNode(d - 1);
            }
        }

        internal static int Check(TreeNode current)
        {
            int c = 0;
            while (current != null)
            {
                c += Check(current.right) + 1;
                current = current.left;
            }
            return c;
        }
    }

    const int MinDepth = 4;
    const int NoTasks = 4;

    public static void Main(string[] args)
    {
        int maxDepth = args.Length == 0 ? 10
            : Math.Max(MinDepth + 2, int.Parse(args[0]));


        long startTime = DateTime.Now.Ticks / TimeSpan.TicksPerMillisecond;

        Console.WriteLine(string.Concat("stretch tree of depth ", maxDepth + 1,
            "\t check: ", TreeNode.Check(new TreeNode(maxDepth + 1))));

        var longLivedTree = new TreeNode(maxDepth);

        var results = new string[(maxDepth - MinDepth) / 2 + 1];

        for (int i = 0; i < results.Length; i++)
        {
            int depth = i * 2 + MinDepth;
            int n = (1 << maxDepth - depth + MinDepth) / NoTasks;
            var tasks = new Task<int>[NoTasks];
            for (int t = 0; t < tasks.Length; t++)
            {
                tasks[t] = Task.Run(() =>
                {
                    var check = 0;
                    for (int i = n; i > 0; i--)
                        check += TreeNode.Check(new TreeNode(depth));
                    return check;
                });
            }
            var check = tasks[0].Result;
            for (int t = 1; t < tasks.Length; t++)
                check += tasks[t].Result;
            results[i] = string.Concat(n * NoTasks, "\t trees of depth ",
                depth, "\t check: ", check);
        }

        for (int i = 0; i < results.Length; i++)
            Console.WriteLine(results[i]);

        Console.WriteLine(string.Concat("long lived tree of depth ", maxDepth,
            "\t check: ", TreeNode.Check(longLivedTree)));

        long end = DateTime.Now.Ticks / TimeSpan.TicksPerMillisecond;

        Console.WriteLine(string.Concat("time: ", end - startTime, "ms"));
    }
}