/in/foo.cc: In constructor 'Poly::Poly(std::vector<Coor>)':
/in/foo.cc:110:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 1; i < _v.size(); i++) {
                         ~~^~~~~~~~~~~
/in/foo.cc: In member function 'int Poly::judge(Line)':
/in/foo.cc:119:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < v.size(); i++) {
                         ~~^~~~~~~~~~
/in/foo.cc: In member function 'std::pair<Poly, Poly> Poly::getPair(Line)':
/in/foo.cc:149:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < v.size(); i++) {
                         ~~^~~~~~~~~~
/in/foo.cc:175:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = id[1]; i < v.size(); i++) {
                             ~~^~~~~~~~~~
/in/foo.cc:179:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < tv[0].size(); i++) {
                         ~~^~~~~~~~~~~~~~
/in/foo.cc:184:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < tv[1].size(); i++) {
                         ~~^~~~~~~~~~~~~~
/in/foo.cc: In member function 'bool Poly::isOnBorderOrOut(Coor)':
/in/foo.cc:194:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < v.size(); i++) {
                         ~~^~~~~~~~~~
/in/foo.cc: In member function 'bool Poly::isPointIn(Coor)':
/in/foo.cc:210:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < v.size(); i++) {
                         ~~^~~~~~~~~~
/in/foo.cc: In function 'std::ostream& operator<<(std::ostream&, const Poly&)':
/in/foo.cc:222:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < p.v.size() - 1; i++) {
                         ~~^~~~~~~~~~~~~~~~