public override void Run()
        {
            var root = Create(0, 1, 2, 3, 4, 5, 6);

            BTreePrinter.Print(root);
            Console.WriteLine("Solution 1");
            var sol1   = new Solution1();
            var result = sol1.Convert(root);

            Display(result.Head);

            Console.WriteLine("Solution 2");
            root = Create(0, 1, 2, 3, 4, 5, 6);
            var sol2    = new Solution2();
            var result2 = sol2.Convert(root);

            Display(result2);

            Console.WriteLine("Solution 3");
            root = Create(0, 1, 2, 3, 4, 5, 6);
            var sol3    = new Solution3();
            var result3 = sol3.Convert(root);

            Display(result3);
        }