Reverse Words in a String-LeetCode

Reverse Words in a String--LeetCode

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

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

Update (2015-02-12):
For C programmers: Try to solve it in-place in O(1) space.

思路：做两次旋转 和Rotate Array相似

void reverseChar(string& s,int begin,int end)
{
     if(end < begin)
      return ;
     while(begin <= end)
     {
         swap(s[begin],s[end]);
         begin++;
         end--;        
     }
}
void reverseWords(string &s) 
{
     int len = s.length();
     int i,j;
     reverseChar(s,0,len-1);
     for(i=0;i<len;)
     {
        for(j=i;j<len;j++)
          if(s[j] == ' ')
            break;
        reverseChar(s,i,j-1);
        i = j+1;
     }       
}