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Write a quine... from which every other character can be removed it still be a valid quine. You can specify whether to start removing characters at the first or second character.

Scoring criteria (add bonuses/penatly percentages together for total percentage):

  • Answers must be at least 4 characters long
  • Program must contain at least one alphabetical character in its source, so for example, 12345!@#$%^&*() is disqualified
  • +750% if the language used is not Turing-complete (I'm looking at you, HTML!)
  • -15% if the solution does not read its source from anywhere in any form
  • -20% if you can also keep only every 5th character and still form a quine

The score is measured by the number of characters in the first program.

Example (not real programs):

If 123456789abcdef and 13579bdf are both quines, the score is 15. Additionally, if 159d is also a quine, then the final score is 12.

This is code-golf, so lowest score wins.

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@hosch250 The original program wouldn't be a quine because it wouldn't print those whitespaces. Same goes for unnecessary comments. –  Jwosty Mar 7 at 5:26
Yeah, I have never programed a quine before, and have no idea how to do it without reading the source code in C++. I have seen them in C++ before though! –  hosch250 Mar 7 at 5:37
You state: "-20% if you can also remove every 4 characters and still form a quine". But technically this is not what happens in your example. You mean you can do it a second time? –  mmumboss Mar 7 at 8:17
Are the bonuses additive or multiplicative? That is, if my program is 10 chars long and qualifies for both the -15% bonus and the -20% bonus, will its score be 10 * (1 - 0.15 - 0.2) = 6.5 or 10 * (1 - 0.15) * (1 - 0.2) = 6.8? I assumed the latter, but an explicit clarification would be nice. –  Ilmari Karonen Mar 7 at 10:26
Wouldn't this be a Mandoline quine, not a Guillotine? Guillotines make one clean, generally fatal, cut and the head rolls away. Mandolines make with the many evenly spaced slices. :) –  Jonathan Van Matre Mar 7 at 21:45
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11 Answers 11

PHP, 4 chars − 15% − 20% = 2.72 2.6 points


Yes, PHP is a Turing-complete language. Nobody said I have to use any of its actual programming features. ;-)

Edit: Changed the score based on the clarification that bonuses are additive, not multiplicative.

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This works in ASP, possibly. –  Ismael Miguel Mar 7 at 14:03
+1. Just to show how crappy the specification is. –  n̴̖̋h̷͉̃a̷̭̿h̸̡̅ẗ̵̨́d̷̰̀ĥ̷̳ Mar 7 at 20:33
@n̴̖̋h̷͉̃a̷̭̿h̸̡̅ẗ̵̨́d̷̰̀ĥ̷̳ I give up. :P –  Jwosty Mar 8 at 4:35
Actually, use of PHP's actual programming features is discouraged. –  Rhymoid Mar 8 at 18:21
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python - 95

Great challenge. I thought this was pretty clever, and actually a legit solution!

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Nice! Note this technically doesn't work as-is since you end up deleting the newline when making the alternate quine. requires a tad bit of tweaking IOW –  Claudiu Mar 7 at 5:44
@Claudiu Well I guess it depends on whether OP considers newline a character. If so, you can just add a newline between each line. 96 chars –  qwr Mar 7 at 5:47
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TI BASIC 4 - 35% = 2.6

I might understand them wrong, but I think I am also eligible for the -15% and the -20% bonusses, meaning I have the lowest possible score.

I can write the program:


which will output 123i where i is of course the imaginary unit. When you remove the 1st and the 3rd character all that remains is 2i which outputs 2i

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Not quite... '12i' will output '12i' and '2' will output '2' for a minimum score of 1.95. –  intx13 Mar 7 at 11:33
Actually, '2i' scores 1.3, and if the empty program is considered a quine, 'i' scores 0.65. –  intx13 Mar 7 at 11:36
@intx13: "Answers must be at least 4 characters long." –  Ilmari Karonen Mar 7 at 14:02
Ah, I missed that! –  intx13 Mar 7 at 18:14
Beat me to it ;) –  Timtech Mar 8 at 0:40
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Golfscript, 5 points


is a function that, when executed, will run the (non-existing) function hai. It's not executed, however, but rather printed when the program ends - including the outer brackets. Removing each other character yields:


Lame, I know :-)

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I believe you qualify for both bonuses, too: your program does not read its own source code, and {} is a quine too. –  Ilmari Karonen Mar 7 at 10:21
@IlmariKaronen it's hard to tell what counts as reading own source code. Does unevaluating functions count? Does evaluating strings count? As for the other bonus - maybe it's just badly worded, but I read "remove every four characters" as "keep every fifth character", which would leave me with one bracket only (though {ab0} qualifies if 0 can be the one that's kept) –  Jan Dvorak Mar 7 at 10:40
It's indeed badly worded, but the example suggests it means "keep every fourth character". Anyway, as you note, {ab0} qualifies either way. –  Ilmari Karonen Mar 7 at 10:44
It seems {hi} also works, will be shorter (4 chars), and will also qualify for all bonuses. (Seems the script {i evaluates to {i for some reason...) –  Claudiu Mar 7 at 16:59
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HTML/Markdown, 4*7.5 = 30


I admit this is lame, but it doesn't really go against any rule in the question. Except that HTML/Markdown may not be considered a real programming language.

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I suppose I didn't specify that programs that can't be split any smaller aren't valid. Revising challenge... –  Jwosty Mar 7 at 5:38
@Jwosty: then "HHHH" in HTML would win. Note 5555 doesn't work because it has no alphabetic character –  Claudiu Mar 7 at 5:42
You need an alphabetic character. –  qwr Mar 7 at 5:43
@qwr: Forgot that when looking at GolfScript. Removed. –  n̴̖̋h̷͉̃a̷̭̿h̸̡̅ẗ̵̨́d̷̰̀ĥ̷̳ Mar 7 at 5:44
Hmm... I suppose that this valid :P –  Jwosty Mar 7 at 5:50
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HQ9+ - 4 * 7.5 * 0.8 = 24 points


Still a quine with every second character:


...and every fifth:


Sorry, I couldn't resist. :)

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I liked qwr's solution so much, I shamelessly made a port for POSIX shell. Please don't save it into a filename containing spaces.

: '#';cat $0

#c a t   $ 0

Start removing at character number 1, and count newlines as characters. The second quine is of course:

 #;a 0
cat $0

Please upvote qwr's answer instead of this one!

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Thanks! sh really makes this some short code. +1 –  qwr Mar 8 at 21:00
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Brainf**k, 37 - 15% = 31.45

Abusing the Portable Brainfuck Interpreter


Start removing from the second character.

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When i run this I get B-C<D+E]F-GÿH<I<J<K<L<M<N<O[P.Q>R] as output so it's lacknig some characters. –  Sylwester Mar 8 at 10:57
Is it Brainfuck, or a particular dialect of Brainfuck that only works on one interpreter? –  immibis Mar 8 at 10:57
@immibis It's regular (those capital letters can be spaces or symbols or anything). However, you must use the portable interpreter linked from the answer. –  Timtech Mar 8 at 12:28
The first part goes left until it finds the ÿ and the linked interpreter happens to store the code 5000 bytes before the start of the data tape. That's hardly portable Brainfuck. –  immibis Mar 8 at 12:40
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Bash, 23

Newline is a character!

Some messy comment work, so that when every other character starting from the first is removed, the comment becomes code and the code becomes a comment:

#cRaRtR R$R0R R#
cat $0

After every other character (including the new line) is removed:

cat $0 #ct$
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it's not a quine if it reads its own source though. –  daniero Apr 13 at 14:58
@daniero "-15% if the solution does not read its source from anywhere in any form" implies that you are allowed to read the program's source (but you don't get the bonus) –  professorfish Apr 13 at 15:39
@daniero oh i looked on wikipedia I suppose it is cheating... but it's code-golf –  professorfish Apr 13 at 15:44
I always upvote cats! –  Antonio Ragagnin Apr 13 at 18:29
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HQ9+T, - 4 * 0.8 = 3.2 points


It's a valid quine (ish) and a quine every second and fifth char. I couldn't resist . . . .

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Julia 2.6

Not as good as the original, but then the original had a problem. This may violate the rules because it has to be run in order to allow p to be defined. Julia predefines two constants pi and im.

julia> p=im

julia> pi
π = 3.1415926535897...

julia> p
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