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Reverse Words in a String

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

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

click to show clarification.

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<iostream>#include<string>#include<sstream>#include<stack>using namespace std;class Solution{public:    void reverseWords(string &s)    {        if(s.empty())            return;        stringstream ss(s);        s.clear();        stack<string> 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<<ss.length()<<endl;    cout<<ss<<endl;    s.reverseWords(ss);    cout<<ss.length()<<endl;    cout<<ss<<endl;}

运行结果:

运行结果:

 

Reverse Words in a String