foo.cc: In function 'int main()':
foo.cc:15:29: warning: 'max' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<FindMaxNeg(a,n1)<<" "<<FindMaxNeg(b,n2);
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
foo.cc:15:26: warning: 'max' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<FindMaxNeg(a,n1)<<" "<<FindMaxNeg(b,n2);
                          ^~~
foo.cc: In function 'int FindMaxNeg(int*, int)':
foo.cc:29:9: warning: 'max' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return max;
         ^~~

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