postfix to infix by ksk

#!ruby -pl
_=o=[]
gsub(/./){x=86%$&[0]&67
_+=[x<4?[0,1].map{|i|x-i>o.pop&66?"(#{_.pop})":_.pop}.reverse*$&:$&]
o<<x}
$_=_

Note that non-ascii characters in the above source code will be escaped (such as \x9f).

download

return top