foo.cc: In function 'int main()':
foo.cc:74:41: warning: operation on 'ptr' may be undefined [-Wsequence-point]
   ans[qr[ptr].ind]=query(i)-query(qr[ptr++].l-1);
                                      ~~~^~
foo.cc:56:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  freopen("P1972_1.in","r",stdin);
  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:57:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  freopen("fuck.out","w",stdout); 
  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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