foo.cc: In function 'int main()':
foo.cc:21:8: warning: unused variable 'y' [-Wunused-variable]
  int x,y,tot=0;
        ^
foo.cc:22:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
  ~~~~~^~~~~~~~~~~~~~
foo.cc:25:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    scanf("%1d",&x),e[i][j]=x;
    ~~~~~~~~~~~~~~~^~~~~~~~~~

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。