class Solution {
public:
    
    void solve(vector<int> nums, vector<int> output, int index, vector<vector<int>> &ans)
    {
        //base case
        if(index>=nums.size())
        {
            ans.push_back(output);
            return;
        }
        
        //eclude
        solve(nums, output, index+1, ans);
        
        //include
        int element = nums[index];
        output.push_back(element);
        solve(nums, output, index+1, ans);
    }
    vector<vector<int>> subsets(vector<int>& nums) {
        
        vector<vector<int>>ans;
        vector<int> output;
        int index=0;
        solve(nums,output,index,ans);
        return ans;
    }
};