Generate all subsets of {0, 1, 2, ..., N-1}

#include <bits/stdc++.h>
using namespace std;

int main() {
    int n;
    cin >> n;
    vector<int> v(n);
    for (int i = 0; i < n; ++i) v[i] = i;
    int m = n;
    while (m > 0) {
        vector<int> curr(m);
        copy(v.begin(), v.begin()+m, curr.begin());
        do {
            for (int x : curr) printf("%i ", x);
            cout << '\n';
        } while (next_permutation(curr.begin(), curr.end()));
        m--;
    }
}