/in/foo.cc: In function 'long long int sub(std::__cxx11::string, long long int)':
/in/foo.cc:26:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while(i<s.size())
        ~^~~~~~~~~
/in/foo.cc:48:24: warning: array subscript has type 'char' [-Wchar-subscripts]
    if(s[i]=='('||f[s[i]]>f[ch[ch_]])
                        ^
/in/foo.cc:55:7: warning: operation on 'd_' may be undefined [-Wsequence-point]
     d[--d_]=cal(d[d_],ch[ch_--],d[d_+1]);
       ^~~~
/in/foo.cc:55:7: warning: operation on 'd_' may be undefined [-Wsequence-point]
/in/foo.cc: In function 'int main()':
/in/foo.cc:71:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(long long i=0;i<n_.size();i++)
                    ~^~~~~~~~~~
/in/foo.cc: In function 'long long int cal(long long int, char, long long int)':
/in/foo.cc:20:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^