/in/p1.cpp: In function 'std::vector<Point> grahamScan(std::vector<Point>&)':
/in/p1.cpp:53:23: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
     for (int i = 1; i < points.size(); ++i)
                     ~~^~~~~~~~~~~~~~~
cc1plus: all warnings being treated as errors