/in/foo.cc: In function 'LL inverse(LL, LL)':
/in/foo.cc:44:6: warning: unused variable 'g' [-Wunused-variable]
  int g=exgcd(a,b,x,y);
      ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:76:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int k=0;k<p.size();k++)
                 ~^~~~~~~~~
/in/foo.cc:85:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       for(int k=0;k<p.size();k++)
                   ~^~~~~~~~~