foo.cc: In function 'int main()':
foo.cc:11:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   11 |         for (int i = 0; i < s.size(); i++)
      |                         ~~^~~~~~~~~~
foo.cc: In function 'int search(std::string, std::string)':
foo.cc:19:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   19 |         for (int i = 0; i < pd.size(); i++)
      |                         ~~^~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务