<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:
    vector<vector<int>> subsetsWithDup(vector<int>& a) {
        sort(a.begin(),a.end());
        vector<vector<int>>ans;
        map<vector<int>,int>v;
        int i,j,n=a.size(),k;
        vector<int>p;
        ans.push_back(p);
        for(i=0;i<n;i++){
            k=ans.size();
            for(j=0;j<k;j++){
                vector<int>p=ans[j];
                p.push_back(a[i]);
                if(v[p]==0){
                    ans.push_back(p);
                    v[p]=1;
                }
            }
        }
        return ans;
    }
};
10108