Problem

Given a set of distinct integers, return all possible subsets.
Note:
Elements in a subset must be in non-descending order.
The solution set must not contain duplicate subsets.
For example,
If nums = [1,2,3], a solution is:
[
  [3],
  [1],
  [2],
  [1,2,3],
  [1,3],
  [2,3],
  [1,2],
  []
]

Solution

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

class Solution {
public:
    vector<vector<int>> subsets(vector<int>& nums) {
        vector<vector<int>> result;
        vector<int> temp;
        sort(nums.begin(), nums.end());
        subsets(nums, 0, temp, result);
        return result;
    }
    
    void subsets(vector<int>& nums, int start, vector<int>& temp, vector<vector<int>>& result) {
        result.push_back(temp);
        for (int i = start; i < nums.size(); i++) {
            temp.push_back(nums[i]);
            subsets(nums, i + 1, temp, result);
            temp.pop_back();
        }
    }
};

int main() {
    Solution s;
    vector<int> nums = {1, 2, 3};
    vector<vector<int>> result = s.subsets(nums);
    for (int i = 0; i < result.size(); i++) {
        for (int j = 0; j < result[i].size(); j++) {
            cout << result[i][j] << " ";
        }
        cout << endl;
    }
    return 0;
}