Permutations

• Time : O(n!)
• Space : O(n!)

#include <vector>
using namespace std;

vector<vector<int>> getPermutations(vector<int> array) {
	  if(array.empty()) return {};
    vector<vector<int>> res;
    do {
        res.push_back(array);
    }while(next_permutation(begin(array), end(array)));
    return res;
}