sub nn{my$x=pop;(sort{$b<=>$a}map{abs($_-$x)}@_)[0,1]}

##</code><code>##

sub nn{my$x=pop;
  (map$_->[0],sort{$a->[1]<=>$b->[1]}map[$_,abs$_-$x],@_)[0,1]}
# or
sub nn2{my$x=pop;
  my@d=map abs$_-$x,@_;@_[(sort{$d[$a]<=>$d[$b]}0..$#_)[0,1]]}