翻转字符串里的单词

class Solution {
public:
    // 此处为自定义的reverse函数，其翻转为左闭右闭[]的翻转
    void reverse(string &s, int start, int end)
    {
        for(int i = start, j = end; i < j; i++, j--)
        {
            swap(s[i], s[j]);
        }
    }

    void removeExtraSpaces(string &s)
    {
        int slow = 0;
        for(int i = 0; i < s.size(); i++)   // 此处slow为慢指针，i为快指针
        {
            if(s[i] != ' ')
            {
                if(slow != 0)
                {
                    s[slow++] = ' ';
                }
                while(i < s.size() && s[i] != ' ')
                {
                    s[slow++] = s[i++];
                }
            }
        }
        s.resize(slow);
    }

    string reverseWords(string s) {
        removeExtraSpaces(s);
        reverse(s, 0, s.size() - 1);
        int start = 0;
        for(int i = 0; i <= s.size(); i++)
        {
            if(i == s.size() || s[i] == ' ')
            {
                reverse(s, start, i - 1);   // 此处为自定义的reverse函数，其翻转为左闭右闭[]的翻转
                start = i + 1;
            }
        }
        return s;
    }
};