foo.cc: In function 'double dg(int, int)':
foo.cc:24:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   24 |  int mid=l+r>>1,i,j;
      |          ~^~
foo.cc: In function 'int main()':
foo.cc:39:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   39 |  scanf("%d",&n);
      |  ~~~~~^~~~~~~~~
foo.cc:41:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   41 |   scanf("%d%d",&d[i].x,&d[i].y);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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