foo.cc: In function 'int main()':
foo.cc:42:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  freopen("7.in", "r", stdin);
  ~~~~~~~^~~~~~~~~~~~~~~~~~~~
foo.cc:43:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     freopen("7.out", "w", stdout);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

正在同步测试数据，请稍后
自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。