foo.cc: In function 'int hb(int*, int, int*, int, int*)':
foo.cc:6:6: warning: 'k' is used uninitialized in this function [-Wuninitialized]
  int k,i=0,j=0;
      ^

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