LeetCode精選100題——第90題——子集 II

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