public void forwardRemove(LinkedList<Integer> digits){
        Iterator<Integer> it = digits.iterator();
        boolean odd = true;
        while (it.hasNext()) {
            it.next();
            if (odd) {
                it.remove();
                odd = false;
            }
            else{
                odd = true;
            }
        }
    }
    public void reverseRemove(LinkedList<Integer> digits){
        if(digits.size() == 1)
            return;
        ListIterator<Integer> it = digits.listIterator(digits.size());
        boolean odd = true;
        while (it.hasPrevious()) {
            it.previous();
            if (odd) {
                it.remove();
                odd = false;
            }
            else{
                odd = true;
            }
        }
    }
    public int lastRemaining(int n) {
        LinkedList<Integer> digits = new LinkedList<>();
        for(int i = 1; i <= n; i++){
            digits.add(i);
        }
        while(digits.size() > 1){
            forwardRemove(digits);
            System.out.println(digits);
            reverseRemove(digits);
            System.out.println(digits);
        }
        return digits.get(0);
    }