foo.cc: In function 'int main()':
foo.cc:9:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    9 |     scanf("%d%d%d",&n,&bgin,&maxlevel);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:13:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   13 |         scanf("%d",&a[i]);
      |         ~~~~~^~~~~~~~~~~~

Found 11 testcases.
[Hydro](https://hydro.ac)提供评测服务