/in/foo.cc: In function 'Polynomial Add(const Polynomial&, const Polynomial&)':
/in/foo.cc:37:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (i < p1.terms.size() && j < p2.terms.size()) {
            ~~^~~~~~~~~~~~~~~~~
/in/foo.cc:37:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (i < p1.terms.size() && j < p2.terms.size()) {
                                   ~~^~~~~~~~~~~~~~~~~
/in/foo.cc:54:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (i < p1.terms.size()) {
            ~~^~~~~~~~~~~~~~~~~
/in/foo.cc:58:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (j < p2.terms.size()) {
            ~~^~~~~~~~~~~~~~~~~