557. Reverse Words in a String III

static int wing=[]()
{
    std::ios::sync_with_stdio(false);
    cin.tie(NULL);
    return 0;
}();

class Solution 
{
public:
    string reverseWords(string s) 
    {
        int len=s.length();
        int pre=-1;
        auto p=s.begin();
        for(int i=0;i<len;i++)
        {
            if(s[i]==' ')
            {
                reverse(p+pre+1,p+i);
                pre=i;
            }             
        }
        reverse(p+pre+1,s.end());
        return s;
    }
};

以空格为标志，一段一段逆置