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.size() == 0)
            return;

        offset = offset % str.size();
        str = str.substr(str.size() - offset, offset) +
                str.substr(0, str.size() - offset);
    }
};