foo.cc: In function 'int main()':
foo.cc:21:30: warning: 'maxneg' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<FindMaxNeg(a, n1)<<" "<<FindMaxNeg(b, n2);
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~
foo.cc:21:27: warning: 'maxneg' 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:36:9: warning: 'maxneg' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return maxneg;
         ^~~~~~

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