foo.cc: In function 'int main()':
foo.cc:15:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d%d",&n,&m,&k,&q);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:27:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&bx[i],&by[i]),block[bx[i]][by[i]]=1;
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
foo.cc:61:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~