/in/foo.cc: In function 'int main()':
/in/foo.cc:26:41: warning: format '%lf' expects argument of type 'double*', but argument 2 has type 'long double*' [-Wformat=]
   scanf("%lf%lf%lf", &x[i], &y[i], &s[i]);
                                         ^
/in/foo.cc:26:41: warning: format '%lf' expects argument of type 'double*', but argument 3 has type 'long double*' [-Wformat=]
/in/foo.cc:26:41: warning: format '%lf' expects argument of type 'double*', but argument 4 has type 'long double*' [-Wformat=]
/in/foo.cc:46:21: warning: format '%lf' expects argument of type 'double', but argument 2 has type 'long double' [-Wformat=]
  printf("%.2lf", ans);
                     ^