foo.cc: In member function 'int PolyList::calculate()':
foo.cc:56:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<PolyListNode>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |   for (int i = 0 ; i < pl.size(); i++)
      |                    ~~^~~~~~~~~~~
foo.cc: In function 'void sumPoly(const PolyList&, const PolyList&)':
foo.cc:63:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<PolyListNode>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   63 |   for (int i = 0; i < pl1.pl.size(); i++)
      |                   ~~^~~~~~~~~~~~~~~
foo.cc:65:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<PolyListNode>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   65 |   for (int i = 0; i < pl2.pl.size(); i++)
      |                   ~~^~~~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务