Postorder

Score: 125.08 (pass)

#!perl -l
sub c{my$j=shift@p;for(pop=~/(.*)$j(.*)/){if(/^.$/){$o.=$_;shift@p}else{c($_)if/./}}$o.=$j}@p=split//,shift;c(pop);print$o

Score: 144.09 (pass)

#!perl -l
sub c{my $j=shift@p;for($_[0]=~/(.*)$j(.*)/){next if/^$/;if(/^.$/){$o.=$_;shift@p;}else{c($_)}}$o.=$j}@p=split//,$ARGV[0];c($ARGV[1]);print$o