public class Solution {
public List<List<Integer>> subsets(int[] nums) {
List<List<Integer>> res = new ArrayList<List<Integer>>();
backtracking(nums, 0, new ArrayList<Integer>(), res);
return res;
}
private void backtracking(int[] nums, int start, List<Integer> temp, List<List<Integer>> res) {
res.add(new ArrayList<Integer>(temp));
for (int i = start; i < nums.length; i++) {
temp.add(nums[i]);
backtracking(nums, i + 1, temp, res);
temp.remove(temp.size() - 1);
}
}
}