LeetCode OJ：Permutations（排列）

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].

排列组合的问题，不用考虑是否发生重复的情况，代码如下：

 class Solution {
 public:
     vector<vector<int>> permute(vector<int>& nums) {
         memset(mark, , sizeof(mark));
         memset(cdds, , sizeof(cdds));
         dfs(, nums.size(), nums);
         return ret;
     }

     void dfs(int dep, int maxDep, vector<int> & nums)
     {
         if(dep == maxDep){
             tmp.clear();
             for(int i = ;i < maxDep; ++i)
                 tmp.push_back(cdds[i]);
             ret.push_back(tmp);
         }else{
             for(int i = ; i < maxDep; ++i){
                 if(!mark[i]){
                     mark[i] = true;
                     cdds[dep] = nums[i];
                     dfs(dep + , maxDep, nums);
                     mark[i] = false;
                 }
             }
         }
     }
 private:
     int cdds[];
     bool mark[];
     vector<int> tmp;
     vector<vector<int>> ret;

 };