foo.cc: In function 'int bfsHash(int, int)':
foo.cc:56:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
foo.cc: In function 'int main()':
foo.cc:59:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%s",arr);
  ~~~~~^~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务