public void TestTwo()
        {
            Tree root = new Tree();//root

            root.x = 8;
            Assert.AreEqual(1, CodilityTreeHeightVisible.Solution(root));
        }
        public void TestOne()
        {
            //Tree t = new Tree() { l = null, r = new Tree() { l = new Tree() { l = null, r = null, x = 30 }, r = null, x = 20 }, x = 10 };
            //Assert.AreEqual(2, CodilityTreeHeightVisible.Solution(t));

            Tree root = new Tree();//root

            root.x     = 8;
            root.l     = new Tree(); //1stlevel
            root.l.x   = 2;
            root.r     = new Tree(); //1stlevel
            root.r.x   = 6;
            root.r.l   = null;
            root.r.r   = null;
            root.l.l   = new Tree(); //2ndlevel
            root.l.l.x = 8;
            root.l.r   = new Tree(); //2ndlevel
            root.l.r.x = 7;

            Assert.AreEqual(2, CodilityTreeHeightVisible.Solution(root));
        }