学步园

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

For example,

Given s = "the sky is blue",

return "blue is sky the".

题意：其实这道题比较简单，就是需要处理一些细节：例如，两个单词之间可能有多个空格，反转后多个空格只保留一个。

class Solution {
public:
    void reverseWords(string &s) {
        int len = s.length();
        vector<string> words;
        int i;
        string word = "";
        for(i=0; i<len; i++)
        {
            if (s[i] == ' ')
            {
                if (word.length() > 0)
                {
                    words.push_back(word);
                }    
                word = "";
                continue;
            }    
            if (i == len - 1)
            {
                word += s[i];
                words.push_back(word);
                continue;
            }    
            word += s[i];
        }  
        len = words.size();
        word = "";
        for(i=len-1; i>=0; i--)
        {
            word += words[i];
            if (i > 0)
            {
                word += " ";
            }    
        }      
        s = word;
    }
};