public class ArrayList{
    public Integer[] list;
    int numElement;

    public ArrayList() {
        list = new Integer[] {0,0,1,1,7,0,1,3};
        numElement = 8;
    }

    public void remove(Integer target) {
        numElement = removeAt(target, 0, 0);
    }

    public int removeAt(Integer target, int cur_index, int array_index) {
        if (cur_index == numElement) {
            return 0;
        }
        if (list[cur_index].compareTo(target) != 0 && list [array_index].compareTo(target) != 0) {
            return (1 + removeAt(target, cur_index + 1, array_index + 1));
        } else {
            while (list[cur_index].compareTo(target) == 0) {
                cur_index++;
            }
            list[array_index] = list[cur_index];
            return (1 + removeAt(target, cur_index + 1, array_index + 1));
        }
    }

    public int removeAt2(Integer target, int cur_index, int array_index){
        if(array_index>=numElement) return cur_index;
        if(list[array_index].compareTo(target)==0)
            return removeAt(target, cur_index, array_index+1);
        list[cur_index] = list[array_index];
        return removeAt(target, cur_index+1, array_index+1);
    }

    public static void main(String[] args){
        ArrayList a = new ArrayList();
        a.remove(1);
        for(Integer i : a.list){
            System.out.println(i);
        }
        System.out.println("num elements " + a.numElement);
    }
}