【leetcode】Permutations II

 1 class Solution {
 2 public:
 3     vector<vector<int> > permuteUnique(vector<int> &num) {
 4        
 5         sort(num.begin(),num.end());
 6         vector<vector<int> > result;
 7         vector<int> tmp;
 8         vector<bool> visited(num.size());
 9         dfs(0,num,result,visited,tmp);
10         return result;
11        
12     }
13    
14    
15     void dfs(int level,vector<int> &num,vector<vector<int> > &result,vector<bool> &visited,vector<int> &tmp)
16     {
17         if(level==num.size())
18         {
19             result.push_back(tmp);
20             return;
21         }
22        
23         for(int i=0;i<num.size();i++)
24         {
25             if(!visited[i])
26             {
27                 if(i>=1&&((num[i]==num[i-1]&&visited[i-1])||(num[i]!=num[i-1]))||i==0)
28                 {
29                     visited[i]=true;
30                     tmp.push_back(num[i]);
31                     dfs(level+1,num,result,visited,tmp);
32                     tmp.pop_back();
33                     visited[i]=false;
34                 }
35             }
36         }
37     }
38    
39 };