foo.cc: In function 'int main()':
foo.cc:16:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d%d",&M,&N,&K);
     ~~~~~^~~~~~~~~~~~~~~~~~~
foo.cc:17:46: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for(i=1;i<=M;i++) for(j=1;j<=N;j++) scanf("%d",&p[i][j]);
                                         ~~~~~^~~~~~~~~~~~~~~

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