字符串的排列

 1 class Solution {
 2 public:
 3     void Permutation(string str,int begin,int end,vector<string>& result)
 4     {
 5         if (begin > end)
 6         {
 7             result.push_back(str);
 8             return;
 9         }
10         for (int i = begin ; i <= end ; ++i)
11         {
12             if(str[begin] != str[i] || begin == i)
13             {
14                 char tem = str[begin];
15                 str[begin] = str[i];
16                 str[i] = tem;
17                 Permutation(str,begin+1,end,result);
18                 tem = str[begin];
19                 str[begin] = str[i];
20                 str[i] = tem;
21             }
22         }
23     }
24     vector<string> Permutation(string str) {
25         vector<string> reslut;
26         if (str.length() == 0)
27             return reslut;
28         Permutation(str,0,str.length()-1,reslut);
29         std::sort(reslut.begin(),reslut.end());
30         return reslut;
31     }
32 };