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".

开头、结尾、中间都可能有多个空格

class Solution {
public:
    void reverseWords(string &s) {
        
        string tmps;
        int tmpi = 0, endi = s.size(), first = 0;
        
        for( ; first < s.size(); ++first )
            if( s[ first ] != ' ' )
                break;
        
        for( int i = s.size()-1; i >= first; --i )
        {
            if( s[ i ] == ' ' )
            {
                if( s[ i+1 ] != '\0' && s[ i+1 ] != ' ' )
                {
                    for( int j = i+1; j < endi; ++j )
                        tmps.push_back( s[ j ] );
                    tmps.push_back( ' ' ); 
                }
                endi = i;
            }
            else if( i == first )
                for( int j = i; j < endi; ++j )
                    tmps.push_back( s[ j ] );
        }
        s = tmps;
    }
};