foo.cc: In function 'int main()':
foo.cc:32:5: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
 if(k=maxk){
    ~^~~~~
foo.cc:33:6: warning: unused variable 'b' [-Wunused-variable]
  int b=k;max2=a[j]; 
      ^
foo.cc:38:15: warning: 'max2' may be used uninitialized in this function [-Wmaybe-uninitialized]
 cout<<max<<" "<<max2;
 ~~~~~~~~~~~~~~^~~~~~

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