foo.cc: In function 'void judge()':
foo.cc:16:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   16 |  freopen("test.in","r",stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
foo.cc:17:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   17 |  freopen("test.out","w",stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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