print all unique subsets

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
 
// Function to print the elements of a vector
void printVector(vector<int> const &out)
{
    for (int i: out)
        cout << i << " ";
    cout << '\n';
}
 
// Recursive function to print all distinct subsets of S
// S    --> input set
// out  --> vector to store subset
// i    --> index of next element in set S to be processed
void findPowerSet(int S[], vector<int> &out, int i)
{
    // if all elements are processed, print the current subset
    if (i < 0)
    {
        printVector(out);
        return;
    }
 
    // include current element in the current subset and recur
    out.push_back(S[i]);
    findPowerSet(S, out, i - 1);
 
    // exclude current element in the current subset
    out.pop_back(); // backtrack
 
    // remove adjacent duplicate elements
    while (S[i] == S[i-1])
        i--;
 
    // exclude current element in the current subset and recur
    findPowerSet(S, out, i - 1);
}
 
// Program to generate all distinct subsets of given set
int main()
{
    int S[] = { 1, 3, 1 };
    int n = sizeof(S) / sizeof(S[0]);
 
    // sort the set
    sort(S, S + n);
 
    // create an empty vector to store elements of a subset
    vector<int> out;
    findPowerSet(S, out, n-1);
 
    return 0;
}