/in/foo.cc: In function 'int main()':
/in/foo.cc:17:21: warning: unused variable 'ans' [-Wunused-variable]
     int n,i,l,r,mid,ans,z,y;
                     ^~~
/in/foo.cc:45:22: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized]
      cout<<z<<endl<<y;
                      ^
/in/foo.cc:45:12: warning: 'z' may be used uninitialized in this function [-Wmaybe-uninitialized]
      cout<<z<<endl<<y;
            ^