<p>Given a collection of numbers, <code>nums</code>,&nbsp;that might contain duplicates, return <em>all possible unique permutations <strong>in any order</strong>.</em></p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> nums = [1,1,2]
<strong>Output:</strong>
[[1,1,2],
 [1,2,1],
 [2,1,1]]
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nums = [1,2,3]
<strong>Output:</strong> [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= nums.length &lt;= 8</code></li>
	<li><code>-10 &lt;= nums[i] &lt;= 10</code></li>
</ul>

class Solution {
public:
    void fun(set<vector<int>>&ans,vector<int>&nums,vector<int>&arr){
        if(nums.size()==0){
            ans.insert(arr);
            return;
        }
        for(int i=0;i<nums.size();i++){
            vector<int>num;
            for(int j=0;j<nums.size();j++){
                if(i!=j){
                    num.push_back(nums[j]);
                }
            }
            arr.push_back(nums[i]);
            fun(ans,num,arr);
            arr.pop_back();
        }
    }
    vector<vector<int>> permuteUnique(vector<int>& nums) {
        set<vector<int>>ans;
        vector<int>arr;
        fun(ans,nums,arr);
        vector<vector<int>>ans1(ans.begin(),ans.end());
        return ans1;
    }
};
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