/in/foo.cc: In function 'int main()':
/in/foo.cc:53:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<v1.size();i++){
               ~^~~~~~~~~~
/in/foo.cc:80:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int i=0;i<v1.size();i++){
                ~^~~~~~~~~~
/in/foo.cc:62:8: warning: unused variable 'bb' [-Wunused-variable]
    int bb=1;
        ^~