LeetCode:151_Reverse Words in a String | 字符串中单词的逆反 | Medium

Given an input string, reverse the string word by word. 

For example,
 Given s = "the sky is blue",
 return "blue is sky the". 

 1 void reverseWords(string &s)
 2 {
 3     int i = 0, j = 0;
 4     string subStr;
 5     vector<string> vecStr;
 6     for (j = 0; j != s.length()+1; ++j) {
 7         if (s[j] == ' '||j == s.length()) { //Ensure that the final substr can be get
 8             subStr = s.substr(i, j - i);
 9             if (subStr != "")  //remove the "" from begin and end str
10                 vecStr.push_back(subStr);
11             i = j + 1;
12         }
13     }
14     
15     int vecLen = vecStr.size();
16     if (vecLen > 0) {  // deal with the s = ""
17         string strResult = "";
18         for (i = vecLen - 1; i > 0; i --) {
19             strResult += vecStr[i] + " ";
20         }
21         strResult += vecStr[i];
22         s = strResult;
23     }
24     else
25         s = "";
26 }

void reverseWords(string & s)
{
    string ss;
    int i = s.length()-1;
    while(i>=0)
    {
        while(i>=0&&s[i] == ' ') //处理多个空格的情况
        {
            i --;
        }
        if(i<0) break;
        if(ss.length()!=0)
            ss.push_back(' ');
        string temp ;
        for(;i>=0&&s[i]!=' ';i--)
            temp.push_back(s[i]);
        reverse(temp.begin(),temp.end());
        ss.append(temp);
    }
    s=ss;
}