Postorder

Score: 53.09 (pass)

#!perl -l
$_=pop;for$~(pop=~/./g){s|$~(.*)|
$1
$~|}print/./g

Score: 54.08 (pass)

#!perl -l
$_=pop;for$~(pop=~/./g){s|$~(\w*)|
$1
$~|}print/./g

Score: 55.09 (pass)

#!perl -l
$_=pop;for$z(pop=~/./g){s/$z(\w*)/ $1 $z/}print/\w/g

Score: 56.09 (pass)

#!perl -l
$_=pop;for$z(pop=~/./g){s/$z(\w*)/ $1 $z/};print/\w/g

Score: 58.10 (pass)

#!perl -l
$_=pop;for$z(pop=~/./g){s/$z(\S*)/ $1 $z/};y/ //d;print

Score: 61.12 (pass)

#!perl -l
$_=pop;s/($&)(\S*)/ $2 $1/while$ARGV[0]=~/./g;y/ //d;print

Score: 80.12 (pass)

#!perl -l
($p,$i)=@ARGV;while($p=~/./g){$r=$&;$i=~s/$r(\S*)/ $1 $r /}$i=~y/ //d;print$i

Score: 111.10 (pass)

#!perl -l
sub z{$_[0]=~/./?do{pop=~/$&/,@_=($`,$',unpack"aa$-[0]a*",pop);z(@_[3,0]).z(@_[4,1]).@_[2]}:pop}print+z@ARGV

Score: 116.10 (pass)

#!perl -l
sub z{$_[0]=~/(.)./?do{pop=~/$1/,@_=(unpack("aa$-[0]a*",pop),$`,$');z(@_[1,3]).z(@_[2,4]).@_[0]}:pop}print+z@ARGV

Score: 117.12 (pass)

#!perl -l
sub p{($_,$z)=@_;/(.)./?do{$z=~/$1/,@_=(unpack("aa$-[0]a*",$_),$`,$');p(@_[1,3]).p(@_[2,4]).@_[0]}:$z}print+p@ARGV

Score: 125.12 (pass)

#!perl -l
sub p{($_,$q)=@_;/(.)./?do{$q=~/$1/,@_=(unpack(aa.$-[0].a.length$',$_),$`,$');p(@_[1,3]).p(@_[2,4]).$_[0]}:$q}print+p@ARGV