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Burrows-Wheeler transform

by shi (Novice)
on Jul 01, 2008 at 17:48 UTC ( #694989=snippet: print w/ replies, xml ) Need Help??
Description: As told by wikipedia the one in the title is a transform useful when compressing data. I spent some minutes on writing these snippets for direct and inverse transformation. May any wise monk help shrinking the code, I'd be thankful and glad to see the results :)
$/="";$l=length($w=<>);map{print+chop}sort+map{substr"$w\0$w",$_,$l+1}
+0..$l

push@w,split//for<>;map{@_=sort@_;$_[$_]=$w[$_].$_[$_]for+0..$#w}0..$#
+w;print+grep{s/\0$//}@_
Replies are listed 'Best First'.
Re: Burrows-Wheeler transform
by moritz (Cardinal) on Jul 01, 2008 at 17:58 UTC
    Unless you're trying to golf, you should strive to make it more readable, not shorter.
      You're right, but I was actually making also a try at golf.
      -- 
      @_=(115,-17,6);print+map{chr$_[$.=$_-$_]*$_**$.+++$_[$.]*$_**$.+++$_[$.]*$_**$.}$.-$...$#_
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