Subsets II

Given a collection of integers that might contain duplicates, nums, return all possible subsets (the power set).

Note: The solution set must not contain duplicate subsets.

Example:

Input: [1,2,2]
Output:
[
  [2],
  [1],
  [1,2,2],
  [2,2],
  [1,2],
  []
]

//Sorting for getting lexiographical order
class Solution {
    public List<List<Integer>> subsetsWithDup(int[] nums) {
        List<List<Integer>> ans = new ArrayList<>();
        List<Integer> temp = new ArrayList<>();
        Arrays.sort(nums);
        backTrack(nums, ans, temp, 0);
        return ans;
    }

    public void backTrack(int[] nums, List<List<Integer>> ans, List<Integer> temp, int start) {
        ans.add(new ArrayList<>(temp));
        for (int i = start; i < nums.length; i++) {
            if (i > start && nums[i] == nums[i - 1])
                continue;
            temp.add(nums[i]);
            backTrack(nums, ans, temp, i + 1);
            temp.remove(temp.size() - 1);
        }
    }
}