foo.cc: In function 'int main()':
foo.cc:43:15: warning: iteration 8010 invokes undefined behavior [-Waggressive-loop-optimizations]
         if(f[i]==1&&std::abs(s-i-i)<min){
            ~~~^
foo.cc:39:14: note: within this loop
     for(i=0;i<80010;i++){
             ~^~~~~~
foo.cc:49:29: warning: 'f2' may be used uninitialized in this function [-Wmaybe-uninitialized]
     std::cout<<f1<<" "<<f2<<"\n";
                             ^~~~
foo.cc:49:20: warning: 'f1' may be used uninitialized in this function [-Wmaybe-uninitialized]
     std::cout<<f1<<" "<<f2<<"\n";
                    ^~~