/in/foo.cc: In function 'bool f1(std::vector<int>&, int)':
/in/foo.cc:8:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < a.size(); i++)
                     ~~^~~~~~~~~~
/in/foo.cc:9:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int j = 0; j < a.size(); j++)
                         ~~^~~~~~~~~~
/in/foo.cc:12:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < b.size(); i++)
                     ~~^~~~~~~~~~
/in/foo.cc:21:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < a.size(); i++)
                     ~~^~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:41:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; a.size()<=T; i++)
                     ~~~~~~~~^~~