<p>Given an integer array <code>nums</code> that may contain duplicates, return <em>all possible</em> <span data-keyword="subset"><em>subsets</em></span><em> (the power set)</em>.</p>

<p>The solution set <strong>must not</strong> contain duplicate subsets. Return the solution in <strong>any order</strong>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> nums = [1,2,2]
<strong>Output:</strong> [[],[1],[1,2],[1,2,2],[2],[2,2]]
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> nums = [0]
<strong>Output:</strong> [[],[0]]
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= nums.length &lt;= 10</code></li>
	<li><code>-10 &lt;= nums[i] &lt;= 10</code></li>
</ul>

class Solution {
public:
    set<vector<int>>st;
    vector<vector<int>>result;
    void solve(vector<int>nums,vector<int>& op){
        if(nums.size()==0){
            if(st.find(op)==st.end()){
                st.insert(op);
                result.push_back(op);
            }
            return;
        }
        vector<int>op1=op;
        vector<int>op2=op;
        op1.push_back(nums[0]);
        nums.erase(nums.begin()+0);
        solve(nums,op1);
        solve(nums,op2);
    }
    vector<vector<int>> subsetsWithDup(vector<int>& nums) {
        sort(nums.begin(),nums.end());
        vector<int>op;
        solve(nums,op);
        return result;
    }
};
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