foo.cc: In function 'void Output(std::vector<Node>&)':
foo.cc:25:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Node>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |         for(int i=0; i<v.size(); i++)
      |                      ~^~~~~~~~~
foo.cc: In function 'std::string bdqc(std::string)':
foo.cc:42:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   42 |         for(int i = 0;i < s.size();i++)
      |                       ~~^~~~~~~~~~
foo.cc:44:29: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   44 |                 if(s[i]>='a'&&s[i]<='z'||s[i]>='A'&&s[i]<='Z')

[Hydro](https://hydro.ac)提供评测服务