/in/foo.cc: In function 'int main()':
/in/foo.cc:21:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while(i<v1.size()&&j<v2.size())
        ~^~~~~~~~~~
/in/foo.cc:21:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while(i<v1.size()&&j<v2.size())
                     ~^~~~~~~~~~
/in/foo.cc:28:8: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(;i<v1.size();i++)
       ~^~~~~~~~~~
/in/foo.cc:30:8: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(;j<v2.size();j++)
       ~^~~~~~~~~~
/in/foo.cc:32:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=0;i<v3.size();i++)
          ~^~~~~~~~~~
/in/foo.cc:7:14: warning: unused variable 't' [-Wunused-variable]
  int na,s,nb,t,i,j;
              ^