LintCode-剑指Offer-(8)旋转字符

class Solution {public:    /**    * @param str: a string    * @param offset: an integer    * @return: nothing    */    void rotateString(string &str,int offset){        //wirte your code here        if (str.length()==0)return;        offset = offset%str.length();        int i =(str.length()-offset)%str.length();        int j = i;        string s;        bool start = true;        while (i!=j|start==true){            s.push_back(str[i]);            i = (i+1)%str.length();            start = false;        }        str = s;    }};