foo.cc: In function 'int main()':
foo.cc:31:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   31 |    scanf("%d",&n);
      |    ~~~~~^~~~~~~~~

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