foo.cc: In function 'int main()':
foo.cc:51:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   51 | scanf("%d",&n); scanf("%s",key);
      | ~~~~~^~~~~~~~~
foo.cc:51:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   51 | scanf("%d",&n); scanf("%s",key);
      |                 ~~~~~^~~~~~~~~~
foo.cc:57:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   57 | scanf("%d%%",p+j);
      | ~~~~~^~~~~~~~~~~~

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