import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class subsets {
    public static void main(String[] args) {
        int[] arr = {1,2,2};
        System.out.println(susbsetDuplicate(arr));
    }

    private static List<List<Integer>> susbsetDuplicate(int[] arr) {
        Arrays.sort(arr);
        List<List<Integer>> outer = new ArrayList<>();
        outer.add(new ArrayList<>());
        int start = 0,end = 0;
        for (int i = 0; i < arr.length; i++) {
            start = 0;
            if(i>0 && arr[i] == arr[i-1])
                start = end + 1;
            end = outer.size() -1;
            int n = outer.size();
            for (int j = start; j < n; j++) {
                List<Integer> internal = new ArrayList<>(outer.get(j));
                internal.add(arr[i]);
                outer.add(internal);
            }
        }
        return outer;
    }
}