class Solution {
    public List<List<Integer>> subsets(int[] nums) {
        List<List<Integer>> result = new ArrayList<>();
        List<Integer> temp = new ArrayList<>();

        findAllSubsets(nums, 0, result, temp);
        return result;
    }

    public void findAllSubsets(int[] nums, int index, List<List<Integer>> result, List<Integer> temp)
    {
        // base condition
        if(index == nums.length)
        {
            result.add(new ArrayList<>(temp));
            return;
        }

        // Pick the current element into subset
        temp.add(nums[index]);
        findAllSubsets(nums, index+1, result, temp);
        // do not pick the current element into subset
        temp.remove(temp.size()-1);
        findAllSubsets(nums, index+1, result, temp);
        return;
    }
}