/in/foo.cc: In member function 'bool PE615::elem::operator<(const PE615::elem&) const':
/in/foo.cc:70:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(i=0,j=0;i<a.size() || j<a2.size();){
                ~^~~~~~~~~
/in/foo.cc:70:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(i=0,j=0;i<a.size() || j<a2.size();){
                              ~^~~~~~~~~~
/in/foo.cc:72:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if(j==a2.size()){
        ~^~~~~~~~~~~
/in/foo.cc:75:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     }else if(i==a.size()){
              ~^~~~~~~~~~
/in/foo.cc: In member function 'PE615::elem PE615::elem::insert_delete(LL, LL)':
/in/foo.cc:102:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int i=0;i<a.size();i++){
                ~^~~~~~~~~
/in/foo.cc: In member function 'void PE615::elem::output()':
/in/foo.cc:121:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int i=0;i<a.size();i++)
                ~^~~~~~~~~
/in/foo.cc: In function 'int PE615::main(LL, LL, LL)':
/in/foo.cc:153:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int i=0;i<e1.a.size();i++){
                ~^~~~~~~~~~~~
/in/foo.cc:162:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<e1.a.size();i++)
               ~^~~~~~~~~~~~
/in/foo.cc:165:2: warning: no return statement in function returning non-void [-Wreturn-type]
  }
  ^