/in/foo.cc: In member function 'double Solution::combine(std::vector<point>&, double, int)':
/in/foo.cc:37:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < points.size(); i++)
                   ~~^~~~~~~~~~~~~~~
/in/foo.cc: In member function 'double Solution::closest(std::vector<point>&)':
/in/foo.cc:63:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = mid ; i < points.size(); i++)
                      ~~^~~~~~~~~~~~~~~