leetcode 541.反转字符串II

class Solution {
public:
    string reverseStr(string s, int k) {
        for(int i=0;i<s.size();i+=(2*k)){
            if(i+k<=s.size()){
                reverse(s.begin()+i,s.begin()+i+k);
            }else{
                reverse(s.begin()+i,s.end());
            }
        }
        return s;
    }


};