leetcode90 Subsets II

Given a collection of integers that might contain duplicates, nums, return all possible subsets.

Note:

• Elements in a subset must be in non-descending order.
• The solution set must not contain duplicate subsets.

For example,
If nums = [1,2,2], a solution is:

[
  [2],
  [1],
  [1,2,2],
  [2,2],
  [1,2],
  []
]

class Solution {
public:
    vector<vector<int>> subsetsWithDup(vector<int>& nums) {
        sort(nums.begin(),nums.end());
        vector<vector<int>> ans;
        vector<int> cur;
        ans.push_back(cur);
        dep(ans,nums,0,cur);
        return ans;
    }
    void dep(vector<vector<int>>&ans,vector<int>&nums,int pos,vector<int>&cur)
    {
        int size=nums.size();
        if(pos>=size)
            return;
        for(int i=pos;i<size;i++)
        {
            if(i!=pos&&nums[i]==nums[i-1])
                continue;
            
            cur.push_back(nums[i]);
            ans.push_back(cur);//解决自某个元素后都不选则添加不进结果集的情况
            dep(ans,nums,i+1,cur);
            cur.erase(cur.end()-1);
        }
    }
};