foo.cc: In function 'bool check(int, int)':
foo.cc:10:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<sen[p].size();i++)
                 ~^~~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:49:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<sen.size();i++)
                 ~^~~~~~~~~~~
foo.cc:70:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<sen.size();i++)
                 ~^~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务