foo.cc: In function 'int MIN(int, int)':
foo.cc:22:10: warning: 'max' may be used uninitialized in this function [-Wmaybe-uninitialized]
  min = (x/max)*y;     //x*y=min*max 
        ~~^~~~~
foo.cc: In function 'int main()':
foo.cc:22:10: warning: 'max' may be used uninitialized in this function [-Wmaybe-uninitialized]
  min = (x/max)*y;     //x*y=min*max 
        ~~^~~~~
foo.cc:6:14: note: 'max' was declared here
  int i,z,min,max;
              ^~~
foo.cc:22:10: warning: 'max' may be used uninitialized in this function [-Wmaybe-uninitialized]
  min = (x/max)*y;     //x*y=min*max 
        ~~^~~~~
foo.cc:6:14: note: 'max' was declared here
  int i,z,min,max;
              ^~~

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