/**
knakul853
**/
class Solution {
public:
    vector<vector<int>> permute(vector<int>& nums) {

        vector<vector<int> >ans;
        backtrack( nums , 0 , ans );
        return ans;

    }

    void backtrack(vector<int>& nums , int id , vector<vector<int> >&ans)
    {
        if(id == nums.size())
        {
            ans.push_back(nums);
            return ;
        }

        for(int i = id ; i < nums.size();i++)
        {
            swap(nums[i] , nums[id]);
            backtrack(nums , id+1 , ans );
            swap(nums[i] , nums[id]);
        }


    }
};