leetcode 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

".

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.

具体实现见代码，值得注意的是在反转的过程中本来用的是char *数组，使用sprintf一直报OLE错误，后来改用string的append就可以了。参考代码两个方法实现，其中第二个参考网上的，效率其实差不多。。。但是代码确实精简很多。。。

#include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <algorithm>
#include <map>
#include <stack>
#include <cmath>
#include <queue>
#include <set>
#include <list>
#include <cctype>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define REP(i,j,k) for(int i = j ; i < k ; ++i)
#define MAXV (1000)
#define INF (0x6FFFFFFF)
using namespace std;

class Solution
{
public:
void reverseWords(string &s) {
bool first = true;
const char *x = s.c_str();
int word_start[100000]= {0};//记录一个单词的开始下标
int word_end[100000]= {0};//记录一个单词的结束下标
int cnt = 0;
unsigned i=0;
for(;;) {
while(x[i]==' ')//跳过空格
++i;
if(i >= s.size())
break;
word_start[cnt] = i;//记录单词的开始位置
while(x[i]!=' '&&x[i]!='\0')
++i;
word_end[cnt++] = i-1;//记录单词的结束位置
}
string str;
while(cnt--) {//从后往前将单词append到str中
char temp_s[100000];//一个单词
int t=word_end[cnt]-word_start[cnt]+1;
int temp_cnt=word_start[cnt],j=0;
for(j=0; j<t; ++j) {
temp_s[j]=x[temp_cnt++];
}
temp_s[j]=0;//位置j置0表示单词结束
if(first) {
str.append(temp_s);
first = false;
} else
str.append(" ").append(temp_s);
}
s = str;
cout<<s<<"*111"<<endl;
}
void reverseWords1(string &s) {
string rs;
for (int i = s.length()-1; i >= 0; ) {
while (i >= 0 && s[i] == ' ') i--;
if (i < 0) break;
if (!rs.empty()) rs.push_back(' ');
string t;
while (i >= 0 && s[i] != ' ') t.push_back(s[i--]);
reverse(t.begin(), t.end());
rs.append(t);
}
s = rs;
cout<<s<<"*222"<<endl;
}
};

int main()
{
//freopen("in.txt","r",stdin);
Solution s;
string kk = "  I love!!      you so much   ";
string k1 = kk;
string k2 = kk;
s.reverseWords1(k1);
s.reverseWords(k2);
return 0;
}