90.子集II

class Solution {public List<List<Integer>> subsetsWithDup(int[] nums) {List<List<Integer>> ans = new ArrayList<>();List<Integer> list = new ArrayList<>();//排序后便于去重Arrays.sort(nums);dfs(0,nums,ans,list);return ans;}private void dfs(int begin,int[] nums,List<List<Integer>> ans,List<Integer> list){ans.add(new ArrayList<>(list));for(int i = begin;i<nums.length;i++){//去重if(i > begin && nums[i] == nums[i-1]){continue;}list.add(nums[i]);dfs(i+1,nums,ans,list);list.remove(list.size()-1);}}
}