Subsets

Subsets

Given a set of distinct integers, nums, return all possible subsets.

Note:

• Elements in a subset must be in non-descending order.
• The solution set must not contain duplicate subsets.

For example,
If nums = [1,2,3], a solution is:

[  [3],  [1],  [2],  [1,2,3],  [1,3],  [2,3],  [1,2],  []]

public class Solution {    public List<List<Integer>> subsets(int[] nums) {        Arrays.sort(nums);        List<List<Integer>> ret = new ArrayList<List<Integer>>();        List<Integer> list = new ArrayList<Integer>();                helper(ret,list,nums,0);        return ret;    }        private void helper(List<List<Integer>> ret,List<Integer> list,int[] nums,int position) {                ret.add(new ArrayList<Integer>(list));                for (int i = position; i < nums.length; i++) {            list.add(nums[i]);            helper(ret,list,nums,i + 1);            list.remove(list.size()-1);        }    }}