foo.cc: In function 'int Searchsum(long long int*, long long int, long long int)':
foo.cc:11:9: warning: 'cnt' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return cnt;
         ^~~
foo.cc: In function 'long long int xmax(long long int*, long long int)':
foo.cc:21:3: warning: 'j' may be used uninitialized in this function [-Wmaybe-uninitialized]
   for(long long j;j<add[ai];j++)
   ^~~
foo.cc:23:9: warning: 'sum' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return sum;
         ^~~
foo.cc:11:9: warning: 'cnt' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return cnt;
         ^~~
foo.cc:6:12: note: 'cnt' was declared here
  long long cnt;
            ^~~
foo.cc: In function 'int main()':
foo.cc:68:24: warning: 'i' may be used uninitialized in this function [-Wmaybe-uninitialized]
  long long max=xmax(a,i);
                        ^

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