力扣第46题 全排列

力扣第46题 全排列

class Solution {
    public:
    void mySwap(vector<int> &nums, int l, int r)
    {
        int temp = nums[l];
        nums[l] = nums[r];
        nums[r] = temp;
    }

    void backtrack(int n, vector<int> &nums, vector<vector<int>>& res, int idx)
    {
        if (n == idx)
        {
            res.push_back(vector<int>(nums));
            return;
        }
        for (int i = idx; i < n; i++)
        {
            mySwap(nums, i, idx);
            backtrack(n, nums, res, idx + 1);
            mySwap(nums, i, idx);
        }
    }
    
    vector<vector<int>> permute(vector<int>& nums)
    {
        vector<vector<int>> res;
        backtrack(nums.size(), nums, res, 0);
        return res;
    }

};