leetcode - Permutations

Given a collection of numbers, return all possible permutations.

For example,

[1,2,3]

[1,2,3]

[1,3,2]

[2,1,3]

[2,3,1]

[3,1,2]

[3,2,1]

class Solution {
public:
std::vector<std::vector<int> > permute(std::vector<int> &num) {
std::vector<std::vector<int>> res;
std::sort(num.begin(),num.end());
do
{
res.push_back(num);
} while (std::next_permutation(num.begin(),num.end()));
return res;
}
};