Algo_20171016

public static BST Algo_20171016(BST T, int a, int b)
{
    if (T != null)
    {
        Console.WriteLine($"T: {T.key}, a: {a}, b: {b}");

        if (T.key >= a && T.key <= b)
        {
            T.sx = Algo_20171016(T.sx, a, T.key);
            T.dx = Algo_20171016(T.dx, T.key, b);
        }
        else
        {
            Cancella(T);
            T = null;
        }
    }

    return T;
}

public static BST Algo_20171016_Miky(BST T, int a, int b)
{
    BST last = null;
    BST next = null;
    BST curr = T;
    var S = new Stack<BST>();

    var Sa = new Stack<int>();
    var Sb = new Stack<int>();

    while (S.Count > 0 || curr != null)
    {
        if (curr != null)
        {
            S.Push(curr);
            Sa.Push(a);
            Sb.Push(b);

            Console.WriteLine($"T: {curr.key}, a: {a}, b: {b}");

            if (curr.key >= a && curr.key <= b)
            {
                next = curr.Sx;
                b = curr.key;
            }
            else
            {
                var sono_sinistro = curr.Equals(last.sx);

                Cancella(curr);
                curr = null;
                next = null;
                S.Pop();
                Sa.Pop();
                Sb.Pop();

                if (sono_sinistro)
                    last.sx = null;
                else
                    last.dx = null;
            }
        }
        else
        {
            curr = S.Peek();
            a = Sa.Peek();
            b = Sb.Peek();

            if (curr.Dx != null && curr.Dx != last)
            {
                if (curr.key >= a && curr.key <= b)
                {
                    next = curr.Dx;
                    a = curr.key;
                }
            }
            else
            {
                next = null;
                S.Pop();
                Sa.Pop();
                Sb.Pop();
            }
        }

        last = curr;
        curr = next;
    }

    return T;
}