leetcode557 C++ 56ms 反转字符串中的每个单词

class Solution {
public:
    string reverseWords(string s) {
        auto st = s.begin();

        for(auto i = s.begin();i<s.end();i++){
            if(*i == ' '){
                reverse(st, i);
                st = i + 1;
            }
        }
        reverse(st, s.end());
        return s;
    }
};