Leetcode 46 Permutations Solutions

Problem Statement could be found @https://leetcode.com/problems/permutations/

class Solution {
   
    vector<vector<int>> retvec;
public:

void swap(vector<int> &nums, int i, int j){
    int temp = nums[i];
    nums[i] = nums[j];
    nums[j] = temp;
}

void helper(vector<int> &nums, int index){
    if (index == nums.size()){
        retvec.push_back(nums);
        return ;
    }
    for (int i=index; i< nums.size();i++){
       
        swap(nums, i, index);
        helper(nums, index+1);
        swap(nums, i, index);
    }
   
}
    vector<vector<int>> permute(vector<int>& nums) {
       
        helper(nums,0);
        return retvec;
    }
};