Permutations

<-M 46> Permutations

class Solution {
public:
    vector<vector<int>> permute(vector<int>& nums) {
        sort(nums.begin(), nums.end());

        vector<vector<int>> result;
        vector<int> path;

        dfs(nums, path, result);
        return result;
    }
private:
    void dfs(const vector<int>& nums, vector<int> &path, vector<vector<int>> &result) {
        if(path.size() == nums.size()) {
            result.push_back(path);
            return;
        }
        for(auto i : nums) {
            auto pos = find(path.begin(), path.end(), i);
            if(pos == path.end()) {
                path.push_back(i);
                dfs(nums, path, result);
                path.pop_back();
            }
        }
    }
};