foo.cc: In function 'int main()':
foo.cc:6:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    6 | scanf("%d%d",&t,&n);
      | ~~~~~^~~~~~~~~~~~~~
foo.cc:9:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    9 |     scanf("%d",&v[i]);
      |     ~~~~~^~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务