foo.cc: In function 'int main()':
foo.cc:19:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d", &n);
 ~~~~~^~~~~~~~~~
foo.cc:34:7: warning: ignoring return value of 'int system(const char*)', declared with attribute warn_unused_result [-Wunused-result]
 system("pause");
 ~~~~~~^~~~~~~~~

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。