vector<vector<int> > permute(vector<int> &num) {

vector<vector<int> > res;

sort(num.begin(), num.end());

int n= num.size();

res.push_back(num);

if (n < 2) return res;

while (true){

int i = n-2;

while (i>=0 && num[i] >= num[i+1]) i--;

if (i>=0){

int j= n-1;

while (num[j]<=num[i]){

j--;

}

swap(num[i], num[j]);

for (int l = i+1, r = n-1; l<r; l++, r--)

swap(num[l], num[r]);

res.push_back(num);

}else

break;

}

return res;

}