foo.cc: In function 'int main()':
foo.cc:39:63: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         for(int i=1;i<=n;i++) scanf("%lf %lf",&a[i].x,&a[i].y),tmp[i]=a[i];
                               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~

正在同步测试数据，请稍后
[Hydro](https://hydro.ac)提供评测服务