public boolean add(E obj) {
        int pos = Math.abs(obj.hashCode() % mas.length);

        if (mas[pos] != null) {
            Link iter = mas[pos];
            while (iter.next != null) {
                if (iter.value.equals(obj)) {
                    return false;
                }
            }
            iter.next = new Link(obj, null);
        } else {
            mas[pos] = new Link(obj, null);
        }
        return true;
    }