foo.cc: In member function 'void Vector3Array::Sort()':
foo.cc:99:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Vector3>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   99 |   for(int i=0; i<Arr.size(); i++)
      |                ~^~~~~~~~~~~
foo.cc:102:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Vector3>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  102 |    for(int j=i+1; j<Arr.size(); j++)
      |                   ~^~~~~~~~~~~
foo.cc: In function 'std::ostream& operator<<(std::ostream&, const Vector3Array&)':
foo.cc:115:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Vector3>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  115 |   for(int i=0; i<V.Arr.size(); i++)
      |                ~^~~~~~~~~~~~~
foo.cc: In function 'std::istream& operator>>(std::istream&, Vector3Array&)':
foo.cc:121:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Vector3>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  121 |   for(int i=0; i<V.Arr.size(); i++)
      |                ~^~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务