What's the Missing Code? (Cops)

Question 1

Cops' Challenge

It has now been four days since the challenge was posted so all new answers should be marked as non-competing in the title. These answers can still be cracked by robbers but will not go towards their total, and cannot win this challenge.

In this cops-and-robbers challenge, you (the cops) must write a program which prints out a certain string (to STDOUT) when run (and does not error or print to STDERR).
Then, remove a string of consecutive characters from the code so that it still runs (without erroring or printing to STDERR), but does not give the correct output (or gives no output).

Robbers will try to find the correct characters to add back into the code so that it produces the right (case-sensitive) output (except that there may be an extra trailing newline).
The number of characters they find must be less than or equal to the number of characters removed, so if 4 characters were removed and they find a solution adding in only 3 characters, it is still valid.

In your answer, provide:

The language of the code
The code with characters removed (remember, the characters must be consecutive: you can't remove characters from several different places in the code)
How many characters have been removed
The string that the full program outputs (if there is a trailing newline, you may leave that out)

Remember that your answer is still cracked even if the solution found by the robbers was not intended. For this reason, make sure it is not possible for the robbers to simply put some code which says

Print out the string;
End the program.

(In order to stop this happening, try to minimise the number of characters removed while making sure the submission is still challenging. This will also improve your score.)

The score of an answer is equal to: $$ \operatorname{len}(\text{program with chars removed}) + 2 \times \operatorname{len}(\text{chars removed}) $$ or $$ \operatorname{len}(\text{program}) + \operatorname{len}(\text{chars removed}) $$ (They both equate to the same thing).

Make sure to edit your answer if it has been cracked, and link the robber's post. If the robber found an unintended solution, then you may keep the intended solution a secret so that people can still try to find it.

Example submission

Python, score of 14

Code: print(5*"a")
Number of characters removed: 1
Target output: 5 a (currently outputs aaaaa)

This would be very easy to crack as the character , would just need to be added before the *, but it would be valid.

Scoring

The following scoring criterion will be used in order (if #1 is a tie, then #2 is used to tiebreak, etc.):

The cop with the lowest-score uncracked answer after 1 week wins!
Out of the tied cops, the one whose lowest-scored uncracked answer has the most upvotes wins
Out of the tied cops, the one whose lowest-scored most-upvoted uncracked answer was posted first wins

After 4 days, answers posted to this question will be non-competing (but can still be posted), to stop people posting answers just before the week is over and not giving robbers enough time to crack them.

If it has been four days since this was posted (Saturday 2nd April 2022, after whatever time this was posted in your time zone), please mark your answers as "non-competing" in the title.

Robbers can still crack cops' answers for the remaining 3 days and have those count towards their total; however, cracking non-competing cops' answers does not count towards their total.

Good luck!

Question 2

Bit of a n00b question here, but this is my first cops-and-robbers, are cops only allowed to submit one answer, or can you submit multiple?

Question 3

You can submit multiple

Question 4

What's the purpose of the "non-competing" rule? There's no reason not to leave the challenge completely open forever, which is what we do with most cops-and-robbers challenges.

Question 5

If you're going to accept answers, there's one lower-scoring than the current accepted one.

Question 6

Python 3, score 24, cracked by xnor

print((99,15))

5 characters removed
Target output: (6, 9)
Current output: (99, 15)

There's a lot of ways to get 6 but (hopefully) only one to get 5.

Question 7

well I've figured out the 6-byter, now I just gotta figure out what nonsense you do to get it in 5

Question 8

cracked, nice one

Question 9

Java (OpenJDK 8), 547 + 10 = 557 Cracked by Kevin Cruijssen

import static java.util.stream.Collectors.joining;
import java.util.stream.IntStream;
class Program {
 public static void main(String[] args) {
 System.out.println(new Program());
 }
 String getName(int x) {
 return x + " " + Integer.toHexString(x);
 }
 public String toString() {
 return IntStream.of(130, 14, 8613, 8784, 150, 151).mapToObj(x -> {
 String[] s = getName(x).split(" ");
 int n = (x % 13) % 5;
 return s[n % s.length];
 }).collect(joining(" "));
 }
}

Try it online!

I've never done this before and I see my entry is way longer than others. If that's not appropriate let me know and I'll delete it. Of course, Java is infamously verbose. I could also give a hint about what part of my program the characters were deleted from.

10 characters removed
Target output: BREAK OUT FROM THE GUARDED AREA
Current output: 130 e 8613 8784 150 97

So, can the robbers break out from the guarded area?

Question 10

Not bad!! You could probably have made your score a bit lower by golfing out a lot of whitespace and shortening function names & etc, although it definitely wouldnt compete with some of the other answers here cause java

Question 11

cracked Nice answer! You threw me on a loop with the defined getName method, until I realized there is no way it could be modified in just 10 bytes while giving an uppercase output like that.

Question 12

@KevinCruijssen Well done! I knew the getName method, which becomes totally irrelevant once the characters are added back, might throw people off. Very impressive. You have truly broken out from the guarded area. :)

Question 13

Jelly, score = 19

A contiguous string of seven bytes was removed from twelve, leaving these five:

49"»V

Running this as a full program now outputs 0, the output of the original program was:

Dyesters opposredoundse urosthenicupdrying@uniocular alkie Elgar ontic)0e eyednesses Kangarooed TPN harvestbug_| Enviability gilly ophiolaterDenebWorst horsRockierU Huey: Yelt aBA

Try it online!

I don't think this will be easy by any stretch of the imagination, but there are some clever people here who might just find one (of the ones?!) that work out of the \4ドル.3 \times 10^{17}\$ possible programs.

Safe, so how did it work?

I guess this was just a little too much to crack, here's the original program:

 49!’Æfj@)"»V - Link:
 49 - fourty-nine -> 49
 ! - factorial 608281864034267560872252163321295376887552831379210240000000000
 ’ - subtract one 608281864034267560872252163321295376887552831379210239999999999
 Æf - prime decomposition [823,3739397,197653021455862028208110725148879567449727922627417829]
 )"» - list of characters -> ['"', '»']
 @ - with swapped arguments:
 j - join ['"',823,3739397,197653021455862028208110725148879567449727922627417829,'»']
 V - evaluate "82337...829» as Jelly code
 ("...» is Jelly's dictionary-based compression)

Question 14

Just to clarify, 7 + 5 ≠ 13

Question 15

Oops, sorry about that!

Question 16

Is this double compression? I'm starting to wonder if the compressed string is a red herring...

Question 17

@emanresuA despite not really knowing Jelly, I plunged into the docs a bit and tried to reverse engineer this, and it does indeed seem to be double-compressed, as the proper output compresses into a 64-digit number, which interestingly is the product of two primes, but I have no idea what kind of code could create that in Jelly

Question 18

@des54321 A bit late, but there's a semi-optimal string compressor that might help you.

Question 19

Perl 5, score 24, safe

print for a..z

5 characters removed
Target output: ABABABABABABABABABABABABAB
Current output: abcdefghijklmnopqrstuvwxyz

No interpreter flags or trickery involved, this is pure Perl.

Solution


 print<3円>^B for a..z

The code works as is, but replace 3円 with a literal 3円 character to get the claimed score of 5 characters removed.

Question 20

This seems hard! There are several easy (and cheesy) 6 character solutions, but the best I can do in 5 chars is A@A@A@A@A@A@A@A@A@A@A@A@A@.

Question 21

R, score 31, cracked by Dominic van Essen

el(6)

Try it online!

13 characters removed
Target output: "Infant.Mortality"
Current output: 6

Probably too easy for those familiar with R...

Question 22

cracked...

Question 23

By the way, this one was the inspiration for mine. When I saw how you were able to get some built-in text that comes with the language, I started asking myself what other text might be built-in somewhere...

Question 24

Vyxal, 2 + (2 * 4) = 10, safe!

kj

Try it Online!

One last one... Output should be ////\\///\\\//\\\////\\///\\\//\\\////\\///\\\//\\\\///\\///\\\//\\\\///\\///\\\//\\\////\\///\\\//\\\////\\///\\\//\\\////\\///\\\//\\\\///\\///\\\//\\\\///\\///\\\//\\\\///\\///\\\//\\\////\\///\\\//\\\////\\///\\\//\\\\///\\///\\\//\\\\///\\///\\\//\\\\

k/3(:j
Try it Online!
Explanation:
k/ # "/\"
 3( # 3 times...
 :j # Join by itself
Spoilers = pain

Question 25

MATL, score 20. Cracked by Sanchises

'Hey My'

Try it online!

6 characters removed.
Target output: Hey Hey My My (displayed with line feed at the end).
Current output: Hey My (displayed with line feed at the end).

Question 26

what really irritates me about this is you can simply add the missing output to the literal for 7 characters

Question 27

codegolf.stackexchange.com/a/245856/32352 Cracked?

Question 28

@Sanchises Yes! And that was my original code

Question 29

PHP, cracked by dingledooper

Score : 45
Removed 5 consecutive chars
Current output is 38416064248
Expected output is 612510483624

<?php for($i=7;$i-->2;)print$i<<$i;

Edited : removed whitespaces and score was updated in consequence. Also assuming short_open_tag are disabled.

Question 30

Unless I'm missing something, this post's score is \51ドル\,ドル not \39ドル\$.

Question 31

Found something related, though the changing of the second $i to a 1 and the three extra 0s in the output mean that this doesn't work just yet.

Question 32

Cracked, elegant solution!

Question 33

R, score 10 + ×ばつ8 = 26, cracked by Dominic van Essen

print("R")

Try it online!

8 characters removed
Current output: [1] "R"
Target output: [1] R

I haven't done this in a while; I hope I didn't miss an obvious solution!

Question 34

cracked, but probably not the indended solution...

Question 35

@DominicvanEssen Well done, hadn't thought of that! Never matter...

Question 36

I won't post the intended solution yet, as I may be able to salvage the idea for another challenge...

Question 37

Great. I'm terrible at thinking-up challenges, but I love trying to solve them...

Question 38

@DominicvanEssen Here you go!

Question 39

Python, score 36, cracked by dingledooper

"print("")"
print()
""

Attempt This Online!

Add 7 bytes, and output:

print()

Question 40

Cracked

Question 41

JavaScript (Node.js), 13+23*2=59, Cracked

console.log()

Try it online!

Removed 23 characters
Should output 39iw027a2hnuqi2c1os255jmjsidafs3nx6496n8vl8dak0qc3r15xwheq4vxpb136up7rsmbm8v5slowjwf7mvj0s751b03gxif5

Question 42

Cracked

Question 43

Python 3, 23 chars with 4 chars removed = score 27 CRACKED

print(str()[14:18])

Currently outputs nothing, should output Ctrl

Try it online!

Question 44

You placed spoiler TIO link

Question 45

oh shoot @l4m2 thanks for pointing that out

Question 46

its fixed now @l4m2, just no one look at the edit history for the answer :P

Question 47

Cracked (and I didn't look at the edit history)

Question 48

C (C99, clang), 34 bytes removed + 666 bytes total = 700 score

Try it online!

#include <stdio.h>
#include <string.h>
#define p1 2
#define p2 3
#define p3 (p1+p2)
#define p4 p3+p1
#define p5 p4+p1+p1
#define p6 (p5+p1)
#define p7 p6+p1+p1
#define p8 p7+p1
#define ONEHUNDREDTHIRTYONE (p6*p1*p3 + 1)
#define A (p1<<p6)
#define P0 625*p3
#define P P0*P0
#define P3 (P0*p3)*(p1<<p3)
#define B P/A + A/P
#define C(X,Y) X+X+Y*Y
#define D(W,V) C(W,V)*C(V,W)
#define E(M,N) M+N+1
#define F(X) E(X,p2*X)
#define G F(D(E(B,A),(A,B)))
int main()
{
long long a = p1*p1*p1*p1;
a<<=(p8);
a<<=(p8);
a<<=(p6);
a*=ONEHUNDREDTHIRTYONE;
int g = G;
a/=g;
for(int i = 1; i < (g/(P3)) && a!=0; i++)
{
printf("%llX",F(a));
a/=p1;
}
}

Currently outputs 270F665E11387B32F19C3D99794E1ECCBD270F665D1387B32D9C3D9954E1ECC9270F6651387B319C3D994E1ECD270F651387B19C3D94E1ED270F5138799C3D4E1D270D13859C14E12711399D4D251195

Should output 8300000001418000000120C0000001106000000183000000141800000120C000001106000001830000014180000120C00001106000018300001418000120C0001106000183000141800120C001106001830014180120C01106018301418120C1106183141920D105

A lot of preprocessor trickery was used to set up the challenge which sadly makes it a little less competetive lengthwise.

Hint:

In the intended solution there is no character from either [0-9] or [+,-] sets

Question 49

Python 3, 55 bytes + 3 removed = 58 score CRACKED

print("".join(chr(i)for i in b'wZSSP\x1fhPMS[\x1e'))

Currently outputs wZSSPhPMS[ (Plus two unprintables SE markup hates, check TIO link)

Should output Hello World!

Cracked by Sylvester Kruin

Question 50

Cracked it.

Question 51

Lexurgy, Cracked by Jonathan Allan

\7ドル + 2\times 32=71\$ score

a:
*=>w

Characters removed: 32
Target: zwq
Current: w

Original code:

a:
*=>aaa
b:
a=>z/$ _
a=>q/_ $
a=>w

Question 52

Python, 125 + 34 removed = 159 Cracked

import sys
S=sys.stdout
sys.stdout=type('',(),{'write':lambda x,y:'','flush':lambda z:1})()

Attempt This Online!

Not competitive compared to current Python answers, but I imagine people will find the answer Pythonic

Target output:

Gur Mra bs Clguba, ol Gvz Crgref
Ornhgvshy vf orggre guna htyl.
Rkcyvpvg vf orggre guna vzcyvpvg.

Current output: None

Question 53

Given that all other python answers to this have been cracked so far, there isnt exactly much competition for it not to be competitive against

Question 54

Very true. We'll see how this one goes

Question 55

Cracked

Question 56

Vyxal, 3 + (2 * 2) = 7, Cracked by Jonathan Allan.

kay

Try it Online!

Should output acegikmoqsuwy]. Bonus challenge: cegikmoqsuwya.

Question 57

Got it without the bracket, now for that last character...

Question 58

Cracked. The bonus still outstanding.

Question 59

Bonus solution added to that post ^

Question 60

R, score 14 + ×ばつ8 = 30, cracked by Dominic van Essen

`?`=print
?"R"

Try it online!

8 characters removed
Current output: [1] "R"
Target output: [1] R

This is my second attempt, after Dominic van Essen found an unintended crack to my first attempt. I hope this one is more robust!

Question 61

Cracked!. I discovered the n*****e function for the first time while trying to crack your previous one (but didn't use it there...)....

Question 62

@DominicvanEssen Well done, and still not what I intended! Back to the drawing board...

Question 63

This will probably be my last attempt along this line: codegolf.stackexchange.com/a/245833/86301

Question 64

R, score 24 + ×ばつ8 = 40, cracked by Dominic van Essen

{assign("?",print)}
?"R"

Try it online!

8 characters removed
Current output: [1] "R"
Target output: [1] R

This is my third and probably last attempt, after Dominic van Essen found an unintended crack to my first attempt and then to my second attempt. I hope this one is more robust!

Sisyphus Sisyphus 15.1k3 gold badges48 silver badges89 bronze badges · Accepted Answer · 2022-03-30 02:31:13Z

17

+500

\$\begingroup\$

Python 3, score 24, cracked by xnor

print((99,15))

5 characters removed
Target output: (6, 9)
Current output: (99, 15)

There's a lot of ways to get 6 but (hopefully) only one to get 5.

Share

Improve this answer

edited Mar 30, 2022 at 6:22

answered Mar 30, 2022 at 2:31

Sisyphus's user avatar

Sisyphus Sisyphus

15.1k3 gold badges48 silver badges89 bronze badges

\$\endgroup\$

2

1

\$\begingroup\$ well I've figured out the 6-byter, now I just gotta figure out what nonsense you do to get it in 5 \$\endgroup\$

des54321
– des54321

2022年03月30日 02:58:10 +00:00
Commented Mar 30, 2022 at 2:58
3

\$\begingroup\$ cracked, nice one \$\endgroup\$

xnor
– xnor

2022年03月30日 06:17:05 +00:00
Commented Mar 30, 2022 at 6:17

Add a comment |

What's the Missing Code? (Cops)

Cops' Challenge

Example submission

Python, score of 14

Scoring

28 Answers 28

Python 3, score 24, cracked by xnor

Java (OpenJDK 8), 547 + 10 = 557 Cracked by Kevin Cruijssen

Jelly, score = 19

Safe, so how did it work?

Perl 5, score 24, safe

Solution

R, score 31, cracked by Dominic van Essen

Vyxal, 2 + (2 * 4) = 10, safe!

MATL, score 20. Cracked by Sanchises

PHP, cracked by dingledooper

R, score 10 + ×ばつ8 = 26, cracked by Dominic van Essen

Python, score 36, cracked by dingledooper

JavaScript (Node.js), 13+23*2=59, Cracked

Python 3, 23 chars with 4 chars removed = score 27 CRACKED

C (C99, clang), 34 bytes removed + 666 bytes total = 700 score

Python 3, 55 bytes + 3 removed = 58 score CRACKED

Lexurgy, Cracked by Jonathan Allan

\7ドル + 2\times 32=71\$ score

Python, 125 + 34 removed = 159 Cracked

Vyxal, 3 + (2 * 2) = 7, Cracked by Jonathan Allan.

R, score 14 + ×ばつ8 = 30, cracked by Dominic van Essen

R, score 24 + ×ばつ8 = 40, cracked by Dominic van Essen

PHP all versions 64 bits, cracked by dingledooper

Rust, \$ 26 + (2 \times 12) = 50\$

MATL, 11 + 14 = 25 (safe)

Intended solution

Vyxal, 3 + (11 * 2) = 25

Python 3, 20 bytes + 3 removed = 23, Cracked by des54321

StackCell, 8 + (11 * 2) = 30 [non-competing, safe]

Behaviour, score = 16 + 2 = 18, cracked by Makonede

JavaScript (Node.js), 35+23*2=81 bytes, safe

C (gcc), 59 bytes + 17 removed = 76 score

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