【LeetCode 20】151.反转字符串里的单词

class Solution {
public:
   string reverseWords(string s){
    reverse(s.begin(),s.end());
    //"  hello world  "
    //" dlrow olleh"
    int cur=0,left=0,right=0,size=s.size();
    
    while(cur<size)
    {
        while(cur<size && s[cur]==' ')
            cur++;
        if(cur==size)
            break;
        if(cur<size&&right>0)
            s[right++]=' ';//w那里加了空格
        left=right;
        while(cur<size&&s[cur]!=' ')
            s[right++]=s[cur++];//往前移去掉了
            //空格，cur到了第一个空格
        reverse(s.begin()+left,s.begin()+right);
        //"worldw olleh"
        //"world w olleh"  cur在空格这里
        //"world helloeh"
    }
    return s.substr(0,right);//返回字符串
   }
};