text: #ifndef REVERSESTRING_HPP_
  #define REVERSESTRING_HPP_
  
  #include <algorithm>
  #include <vector>
  
  void reverseString(std::vector<char>& s) {
    for (int i = 0; i < s.size() / 2; ++i) {
      std::swap(s[i], s[s.size() - i - 1]);
    }
  }
  
  #endif
  