90. Subsets II

去重判断，sort和if (i > pointer && nums[i] == nums[i - 1]) continue;即可

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

public List<List<Integer>> subsetsWithDup(int[] nums) {
    List<List<Integer>> res = new ArrayList<>();
    List<Integer> path = new ArrayList<>();
    Arrays.sort(nums);
    dfs(nums, path, res, 0);
    return res;
}

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