<p>Given an integer array <code>nums</code> of <strong>unique</strong> elements, 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 = [1,2,3]
<strong>Output:</strong> [[],[1],[2],[1,2],[3],[1,3],[2,3],[1,2,3]]
</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>
	<li>All the numbers of&nbsp;<code>nums</code> are <strong>unique</strong>.</li>
</ul>

class Solution {
public:
    // vector<vector<int>> subsets(vector<int>& nums) {
    //     vector<vector<int>> new_nums;
    //     subsets_helper(nums, 0, {}, new_nums);
    //     return new_nums;
    // }

    // void subsets_helper(vector<int>&nums, int index, vector<int>current, vector<vector<int>>&result){
    //     int n = nums.size();
    //     if(index>=n) {
    //         result.push_back(current);
    //         return;
    //     }

    //     current.push_back(nums[index]);
    //     subsets_helper(nums, index+1, current, result);
    //     current.pop_back();
    //     subsets_helper(nums, index+1, current, result);
    // }

    void helper(vector<int> nums, int i, vector<int>&current, vector<vector<int>> &result) {
        int n = nums.size();
        if(i >= n) {
            result.push_back(current);
            return;}

        current.push_back(nums[i]);
        helper(nums, i+1, current, result);
        current.pop_back();
        helper(nums, i+1, current, result);
    }

    vector<vector<int>> subsets(vector<int>& nums) {
        vector<vector<int>> ans;
        vector<int>f;
        helper(nums, 0, f, ans);
        return ans;
    }


};
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