sort-permutations.cc

void findPermutations(vector<int>A, int i, vector<vector<int> >& all){
    if (i == A.size()){
        all.push_back(A);
        return ;
    }
    
    vector<int> sortedCopy(A);
    for(int pos = i; pos < A.size(); ++pos){
        swap(sortedCopy[i], sortedCopy[pos]);
        A = sortedCopy;
        findPermutations(A, i + 1, all);
    }
}

vector<vector<int> > Solution::permute(vector<int> &A) {
    vector<vector<int> > all;
    sort(A.begin(), A.end());
    findPermutations(A, 0, all);
    return all;
    
}