90. Subsets II

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