题目：

题解：

class Solution {List<Integer> t = new ArrayList<Integer>();List<List<Integer>> ans = new ArrayList<List<Integer>>();public List<List<Integer>> subsetsWithDup(int[] nums) {Arrays.sort(nums);int n = nums.length;for (int mask = 0; mask < (1 << n); ++mask) {t.clear();boolean flag = true;for (int i = 0; i < n; ++i) {if ((mask & (1 << i)) != 0) {if (i > 0 && (mask >> (i - 1) & 1) == 0 && nums[i] == nums[i - 1]) {flag = false;break;}t.add(nums[i]);}}if (flag) {ans.add(new ArrayList<Integer>(t));}}return ans;}
}