Leetcode 46. Permutations全排列

Given a collection of distinct integers, return all possible permutations.

Example:

Input: [1,2,3]
Output:
[
  [1,2,3],
  [1,3,2],
  [2,1,3],
  [2,3,1],
  [3,1,2],
  [3,2,1]
]

题目链接：https://leetcode.com/problems/permutations/

体会：很熟，熟能生巧，毕竟是很简单的题

class Solution {
public:
    vector<vector<int>> permute(vector<int>& nums) {
        vector<vector<int>> res;
        fun(res,nums,0,nums.size());
        return res;
    }
    void fun(vector<vector<int>> &res,vector<int> nums,int n,int len)
    {
        if(n==len)
            res.push_back(nums);
        else
        {
            for(int i=n;i<len;i++)
            {
                swap(nums[n],nums[i]);
                fun(res,nums,n+1,nums.size());
            }
        }
    }
};