foo.cc: In function 'void dts::main()':
foo.cc:54:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   54 |         scanf("%d",&n);
      |         ~~~~~^~~~~~~~~
foo.cc:56:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   56 |             scanf("%d",&a[i]),num[i]=i;
      |             ~~~~~^~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务