面试题58 - II. 左旋转字符串

 1 class Solution {
 2 public:
 3     string reverseLeftWords(string s, int n) 
 4     {
 5         reversestr(s, 0, n);
 6         reversestr(s, n, s.size());
 7         reversestr(s, 0, s.size());
 8         return s;
 9 
10     }
11     void reversestr(string &s, int begin, int end)
12     {
13         int i = begin, j = end - 1;
14         char tmp;
15         while(i < j)
16         {
17             tmp = s[i];
18             s[i] = s[j];
19             s[j] = tmp;
20             ++i;
21             --j;
22         }
23     }
24 };