foo.cc: In member function 'bool sqr::to(node&, node&, int)':
foo.cc:71:2: warning: control reaches end of non-void function [-Wreturn-type]
  }
  ^
foo.cc: In function 'bool dir(node&, node&, int&)':
foo.cc:35:2: warning: control reaches end of non-void function [-Wreturn-type]
  }
  ^
foo.cc: In function 'int main()':
foo.cc:99:16: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
                ^
foo.cc:101:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&u,&v),st=node(u,v);
                                  ^
foo.cc:102:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&u,&v),ed=node(u,v);
                                  ^
foo.cc:105:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   q[i]=sqr(x1,y1,x2,y2);
                        ^

自豪的采用 HydroJudger 进行评测(github.com/hydro-dev/HydroJudger)

{"receive":"2020-04-02T11:26:45.609Z","handle":"2020-04-02T11:26:45.609Z","cache_start":"2020-04-02T11:26:45.618Z","read_cases":"2020-04-02T11:26:46.646Z","judge":"2020-04-02T11:26:46.646Z","done":"2020-04-02T11:26:48.337Z"}