foo.cc: In function 'int main()':
foo.cc:18:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d",&n);
 ~~~~~^~~~~~~~~
foo.cc:22:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d %d",&x,&y);
 ~~~~~^~~~~~~~~~~~~~~
foo.cc:26:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 for(int i=1;i<=n;i++) scanf("%d",&w[i]);
                       ~~~~~^~~~~~~~~~~~

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