<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:
void helper(vector<int>& nums,int i, vector<int>& results,set<vector<int>>& subset){
    //base case
    if(i >= nums.size()){
        subset.insert(results);
        return;
    }

    //exclude
    helper(nums,i+1,results,subset);

    //include
    results.push_back(nums[i]);
    helper(nums,i+1,results,subset);
    results.pop_back();

}

    vector<vector<int>> subsetsWithDup(vector<int>& nums) {
        int i = 0;
        vector<int>results;
        set<vector<int>> subset;
        sort(nums.begin(), nums.end());

        helper(nums,i,results,subset);
        vector<vector<int>> result(subset.begin(), subset.end());
        return result;
    }
};
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