<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_subset(vector<int>& nums, vector<vector<int>>& result, vector<bool>& inclusion, unordered_set<string>& dup, int idx) {
        if(idx == nums.size()) {
            vector<int> subset;
            string set_id = "";
            for(int i=0;i<nums.size();i++) {
                if(inclusion[i]) {
                    subset.push_back(nums[i]);
                    set_id += to_string(nums[i]);
                }
            }
            if(dup.find(set_id)!= dup.end()) {
                return;
            }
            dup.insert(set_id);
            result.push_back(subset);
            return;
        }

        helper_subset(nums, result, inclusion, dup, idx+1);
        inclusion[idx] = true;
        helper_subset(nums, result, inclusion, dup, idx+1);
        inclusion[idx] = false;
    }
    vector<vector<int>> subsetsWithDup(vector<int>& nums) {
        sort(nums.begin(), nums.end());
        unordered_set<string> dup;
        vector<bool> inclusion(nums.size(), false);
        vector<vector<int>> result;
        helper_subset(nums, result, inclusion, dup, 0);
        return result;
    }
};
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