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

For example,

Given s = "the sky is blue",

return "blue is sky the".

Clarification:

 

• What constitutes a word?
  A sequence of non-space characters constitutes a word.
• Could the input string contain leading or trailing spaces?
  Yes. However, your reversed string should not contain leading or trailing spaces.
• How about multiple spaces between two words?
  Reduce them to a single space in the reversed string.

提交了好多遍，终于成功了，使用了sstream来分割字符串，使用栈来存放分割之后的字符串，然后出栈就是逆序了。。

 

C++实现代码：

#include
      
       #include
       
        #include
        
         #include
         
          using namespace std;class Solution{public:    void reverseWords(string &s)    {        if(s.empty())            return;        stringstream ss(s);        s.clear();        stack
          
            st;        string tmp;        while(ss>>tmp)        {            st.push(tmp);        }        while(!st.empty())        {            tmp=st.top();            st.pop();            if(!st.empty())                s+=tmp+' ';            else                s+=tmp;        }    }};int main(){    Solution s;    string ss="  the   sky   is    blue  ";    cout<
           
            <
           
          
         
        
       
      

运行结果：

运行结果：