# Description

Given a collection of numbers, return all possible permutations.

For example,
[1,2,3] have the following permutations:

[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1].

The original problem is here.

The original code is here.

# My Solution

I solve this problem in C++, as below:

``````/*
*Permutations
*Author: shuaijiang
*Email: zhaoshuaijiang8@gmail.com
*/
#include<iostream>
#include<math.h>
#include<vector>
#include<stdlib.h>
using namespace std;

class Solution {
public:
vector<vector<int>> permute(vector<int>& nums) {
vector<vector<int>> result;
if(nums.size() <= 0)
return result;
findResult(nums, 0, result);
return result;
}
void findResult(vector<int>& nums, int i, vector<vector<int>> &result){
int size = nums.size();
if(i == size-1){
result.push_back(nums);
return;
}
for(int j=i;j<nums.size();j++){
int temp = nums[i];
nums[i] = nums[j];
nums[j] = temp;

findResult(nums, i+1, result);

temp = nums[i];
nums[i] = nums[j];
nums[j] = temp;
}
}
};
``````

# Note

To solve the problem, recursion is needed. And, we need replace the current number with the numbers after the current.