rev.cc

#include <iostream>
#include <algorithm>
#include <vector>
#include <string>

using namespace std;

class Solution {
public:
    void reverseWords(string &s) {
        if (s.size() <= 1) return;
        
        int i = 0;
        while (i < s.size()) {
            if (s[i] == ' ') {
                i++;
                continue;
            }
            
            int start = i;
            while ((i < s.size()) && (s[i] != ' ')) {
                i++;
            }
            
            int end = i - 1;
            
            cout << "start " << start << " end " << end << endl;
            
            while (start < end) {
                char tmp = s[start];
                s[start] = s[end];
                s[end] = tmp;
                
                start++;
                end--;
            }
        }
        
        reverse(s.begin(), s.end());
    }
};

int main()
{
   Solution sol;
   string input = "hello world!";
   
   sol.reverseWords(input);
   cout << input << endl;
   
   return 0;
}