46. 全排列

 1 class Solution 
 2 {
 3     vector<vector<int>> ans;
 4     vector<int> temp;
 5     vector<bool> st;
 6 public:
 7     vector<vector<int>> permute(vector<int>& nums) 
 8     {
 9         st = vector<bool>(nums.size(),false);
10         dfs(nums,0);
11         return ans;
12     }
13 
14     void dfs(vector<int>& nums,int cur)
15     {
16         if(cur == nums.size())
17         {
18             ans.push_back(temp);
19             return;
20         }
21 
22         //注意i = 0而不是为cur
23         for(int i = 0;i < nums.size();i ++)
24         {
25             if(!st[i])
26             {
27                 st[i] = true;
28                 temp.push_back(nums[i]);
29                 dfs(nums,cur + 1);
30 
31                 temp.pop_back();
32                 st[i] = false;
33             }
34         }
35     }
36 };