Questions tagged [cops-and-robbers]

For challenges which consist of two adversary (and asymmetric) sub-challenges.

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6 votes
12 answers
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Argument of a complex number (Robbers)

V1.1: Added criterion to help with tiebreakers, a bit overkill but still.V1.2: It's April 15th! Task: Crack the scrambled code for calculating the argument of a complex number \$z=x+iy\$ given two ...
CrSb0001's user avatar
  • 361
10 votes
23 answers
2k views

Argument of a complex number (Cops)

This is the cop's thread, where one should post the scrambled code. Here is the robbers' thread where the cracked source should be posted and linked to the cop's answer. NB: I am currently writing up ...
CrSb0001's user avatar
  • 361
0 votes
9 answers
568 views

Can you decrypt me? (Robbers)

Can you decrypt me? Robbers Find any combination of \$n\$ working chars to change and what they should change into, where \$n\$ is chosen by the cop. You cannot change less than n chars, only exactly \...
Larry Bagel's user avatar
  • 4,173
2 votes
9 answers
599 views

Can you decrypt me? (Cops)

Can you decrypt me? Cops Cops, post obfuscated code that hides a number \$n\$ (n must not be greater than the program length) inside its code. If \$n\$ chars are changed (no additions or deletions), ...
Larry Bagel's user avatar
  • 4,173
3 votes
1 answer
227 views

Hashers and Crashers (Robbers)

This is the robbers thread of this cops and robbers challenge. The cops thread is here. Related, but hashes numbers instead of strings and uses a different scoring system. Definitions A hash collision ...
The Empty String Photographer's user avatar
7 votes
1 answer
261 views

Hashers and Crashers (Cops)

This is the cops thread of this cops and robbers challenge. The robbers thread is here. Related, but hashes numbers instead of strings and uses a different scoring system. Definitions A hash collision ...
The Empty String Photographer's user avatar
8 votes
8 answers
645 views

Magic OEIS formulae (Robbers' thread)

This is the robbers' thread. See the cops' thread here. In this cops and robbers challenge, the cops will be tasked with writing an algorithm that computes some function of their choice, while the ...
dingledooper's user avatar
  • 22.7k
12 votes
9 answers
756 views

Magic OEIS formulae (Cops' thread)

This is the cops' thread. See the robbers' thread here. In this cops and robbers challenge, the cops will be tasked with writing an algorithm that computes some function of their choice, while the ...
dingledooper's user avatar
  • 22.7k
11 votes
11 answers
1k views

(Robbers) Fast and Golfiest Season 1: The Lord of the Strings

Fast and Golfiest Robbers Thread Welcome to the first season of Fast and Golfiest, a cops-and-robbers challenge! I designed this challenge to encourage competitive coding for efficiency (fastest ...
Shiran Yuan's user avatar
18 votes
15 answers
1k views

(Cops) Fast and Golfiest Season 1: The Lord of the Strings

Fast and Golfiest Cops Thread Welcome to the first season of Fast and Golfiest, a cops-and-robbers challenge! I designed this challenge to encourage competitive coding for efficiency (fastest ...
Shiran Yuan's user avatar
10 votes
9 answers
2k views

Polyglot Quiz (Robbers' thread)

This is the robbers' thread. For the main rules to this challenge see the cops' thread In this challenge, robbers will choose a cop's vulnerable or safe post and try to figure out a pair of languages ...
Wheat Wizard's user avatar
  • 98.5k
22 votes
15 answers
3k views

Polyglot Quiz (Cops' thread)

This is the cops' thread of a cops-and-robbers challenge. The robbers' thread can be found here In this challenge as a cop you will choose two programming languages A and B, as well as a non-empty ...
Wheat Wizard's user avatar
  • 98.5k
9 votes
10 answers
634 views

Two In One: Guess That Language - Robbers

Cops' challenge This cops-and-robbers challenge challenges the Cop to write a non-empty program that, when run, produces some non-empty output in language A, and, when reversed, produces some non-...
Number Basher's user avatar
19 votes
15 answers
2k views

Two In One: Guess That Language - Cops

Robber's challenge This cops-and-robbers challenge challenges the Cop to write a non-empty program that, when run, produces some non-empty output in language A, and, when reversed, produces some non-...
Number Basher's user avatar
29 votes
21 answers
4k views

Add a hidden language to a polyglot

Inspired/mostly copied but I don't think it's a dupe. Also Inspired. In this challenge, you will create polyglots that include all languages from previous answers, and another language which you won't ...
emanresu A's user avatar
  • 37.8k
10 votes
13 answers
3k views

Robbers: Smallest subset of characters required for Turing Completeness

This is the robbers' challenge. The cops' one is here. In Fewest (distinct) characters for Turing Completeness, the goal is to find the minimum number of characters which make a language Turing ...
Rydwolf Programs's user avatar
29 votes
31 answers
8k views

Smallest subset of characters required for Turing Completeness

In Fewest (distinct) characters for Turing Completeness, the goal is to find the minimum number of characters which make a language Turing Complete...in other words, allow it to do any computation ...
Rydwolf Programs's user avatar
11 votes
19 answers
3k views

What's the Missing Code? (Robbers)

Robbers' Challenge Read the cops' challenge first. In this cops-and-robbers challenge, you (the robbers) must find the correct string of characters, which, when added into the cop's code, will make it ...
Lecdi's user avatar
  • 1,155
27 votes
28 answers
4k views

What's the Missing Code? (Cops)

Cops' Challenge Robbers' challenge here. 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 ...
Lecdi's user avatar
  • 1,155
3 votes
0 answers
129 views

Hello Shue! (Robbers)

Cops thread (read first) Robbers, your task is to find a Shue program p that when given the cops input i, outputs a program <...
AnttiP's user avatar
  • 7,878
4 votes
2 answers
339 views

Hello Shue! (Cops)

Robbers thread In this cops-and-robbers challenge, your task is to write a program h that outputs "Hello Shue!". Next, you have to choose a string ...
AnttiP's user avatar
  • 7,878
8 votes
12 answers
830 views

Slice the source code (Robbers)

Cops thread Robbers Robbers, your job is to find the slices of the corresponding cop's code. Scoring The robber with the most cracks wins. Example Take this code: ...
Larry Bagel's user avatar
  • 4,173
10 votes
13 answers
1k views

Slice the source code (Cops)

Robbers thread Cops Understanding slicing Remember, slices are zero-indexed. Take this slice: [2:]. If the string is "abcde", the result is "cde" because the slice basically means &...
Larry Bagel's user avatar
  • 4,173
14 votes
12 answers
2k views

Output two numbers (Robbers' thread)

This is the robbers' thread to a cops-and-robbers challenge. Click the link to find the cops' thread. In the cops' thread of this challenge, answerers will be writing programs which output two ...
Wheat Wizard's user avatar
  • 98.5k
24 votes
20 answers
2k views

Output two numbers (Cops' thread)

This is the cops' thread to a cops-and-robbers challenge. Click the link to find the robbers' thread. The challenge here is very simple. Create two programs of the same size, in the same language, ...
Wheat Wizard's user avatar
  • 98.5k
8 votes
5 answers
468 views

Inject arbitrary code into a compiler (robbers)

This is the robbers' challenge. To post a cop, go here. In this challenge, cops will invent a (likely simple) programming language, and write an interpreter, transpiler, or compiler that allows you to ...
Rydwolf Programs's user avatar
15 votes
9 answers
934 views

Inject arbitrary code into a compiler (cops)

This is the cops' challenge. To post a robber, go here. In this challenge, cops will invent a (likely simple) programming language, and write an interpreter, transpiler, or compiler that allows you to ...
Rydwolf Programs's user avatar
9 votes
8 answers
481 views

From code to golf (Robbers' thread)

This is a cops-and-robbers challenge, the cops' thread is here You can change the word code into golf by changing a letter at a ...
emanresu A's user avatar
  • 37.8k
13 votes
10 answers
892 views

From code to golf (Cops' thread)

This is a cops-and-robbers challenge, the robbers' thread is here You can change the word code into golf by changing a letter at ...
emanresu A's user avatar
  • 37.8k
7 votes
9 answers
356 views

Find my other token (Robbers)

Cops thread Robbers, Write a program in the cop's language using the cop's P string and your own S string, and the amount of each of them specified in the cop's post. Your S string may not exceed the ...
thejonymyster's user avatar
12 votes
12 answers
859 views

Find my other token (Cops)

Robbers thread Cops, Choose two strings of code, one public and one secret. We will call them P and S. You will be writing a program using only repetitions of these strings. For example: if you choose ...
thejonymyster's user avatar
10 votes
44 answers
3k views

Which character to change (Robbers)

Cops thread Robbers, your task is to crack a cops answer. Reveal the character that should be changed and what it should be changed to too. Please notify the cop if you cracked their challenge. The ...
math scat's user avatar
  • 9,228
20 votes
49 answers
3k views

Which character to change (Cops)

Robbers Thread Cops, your task is to chose a program that prints a string (you can choose). Although, if you change 1 character in your code, it should print another string. But there's a twist: You ...
math scat's user avatar
  • 9,228
15 votes
18 answers
3k views

It almost works (Robbers' Thread)

Cops' Thread Your challenge is to find an uncracked, unsafe cop on the cops thread, and find an input value for which their code does not do as specified by the challenge. You must use values within ...
emanresu A's user avatar
  • 37.8k
27 votes
21 answers
5k views

It almost works (Cops' Thread)

Robbers' Thread Your challenge is to find an existing challenge, and implement it in a way such that certain inputs fail. At least one input must not produce the correct output (use the other ...
emanresu A's user avatar
  • 37.8k
4 votes
2 answers
418 views

Hide a message in an image - Robbers

Choose a challenge from the Cops thread, determine the third hidden message, and describe how the system works. Keep in mind limitations and possibilities available to Cops: You are not expected to ...
Beefster's user avatar
  • 9,931
11 votes
9 answers
892 views

Hide a message in an image - Cops

Robbers thread Your task is to create a method for hiding information in an image. You will post three encoded messages of your choice (keep them classy), each with its associated image. Reveal the ...
Beefster's user avatar
  • 9,931
8 votes
1 answer
389 views

I'm Jelly of Python (Robbers)

What does "jelly" mean in the title?. Cop's thread Robbers, you are to choose an uncracked Cop answer, and attempt to find a Jelly program which is: shorter than the Cop's answer solves the ...
caird coinheringaahin g's user avatar
12 votes
3 answers
1k views

I'm Jelly of Python (Cops)

What does "jelly" mean in the title?. Robber's thread Jelly has an "Evaluate the argument as Python 3" atom, ŒV which takes a string as an ...
caird coinheringaahin g's user avatar
8 votes
4 answers
656 views

The Math is Right, But the Answer is Wrong - Robbers

Challenge The cops created code challenges which result in certain wildly incorrect answers despite correct math. Choose an uncracked, not safe formula from the cop thread. Your task is to find an ...
Beefster's user avatar
  • 9,931
14 votes
4 answers
919 views

The Math is Right, But the Answer is Wrong - Cops

Robber Thread here The Challenge Choose any numeric* formula, algorithm, or code challenge. Implement it in such a way that the math is correct, but at least one answer is wildly** wrong due to some ...
Beefster's user avatar
  • 9,931
11 votes
25 answers
1k views

Almost Illegal Strings, Mark II (Robbers)

This is the robbers' thread for 'Almost Illegal Strings'. See the cop's thread for information on participating. A section from the post is included here for convenience. The Robbers' Challenge Find ...
Sisyphus's user avatar
  • 14.8k
24 votes
27 answers
2k views

Almost Illegal Strings, Mark II (Cops)

Edit 2020-11-06: This challenge has been edited with new provisions to encourage participation. The edits have been bolded for emphasis. Welcome to a cops and robbers version of Find an Illegal ...
Sisyphus's user avatar
  • 14.8k
20 votes
60 answers
6k views

Guess my password (robbers' thread)

Inspired by this challenge, which got closed. This is meant to be an easier, but no less interesting version of that. This is the robbers thread of a cops-and-robbers challenge. For the cops thread, ...
user's user avatar
  • 327
41 votes
68 answers
9k views

Guess my password (cops' thread)

Inspired by this challenge, which got closed. This is meant to be an easier, but no less interesting version of that. This is the cops thread of a cops-and-robbers challenge. For the robbers thread, ...
user's user avatar
  • 327
13 votes
9 answers
1k views

Peel away the layers - Robbers

This is the Robbers thread. For the Cops challenge, see here As the robbers, your job is to crack the cops' answers. Choose an uncracked, unsafe cop answer and attempt to figure out which languages, ...
caird coinheringaahin g's user avatar
28 votes
14 answers
3k views

Peel away the layers - Cops

In this cops-and-robbers challenge, robbers must crack cop answers by finding out which languages the cops used. This is the Cops thread. For the Robbers' challenge, see here Cops, you are to write a ...
caird coinheringaahin g's user avatar
3 votes
0 answers
130 views

Robbers: There's a fault in my vault! [closed]

This is the robbers' thread. The cops' thread is located here. Robber rules Should work for all keys and secrets Should require the same number or fewer guesses as the cop's fault, to prevent brute ...
Rydwolf Programs's user avatar
8 votes
0 answers
1k views

Cops: There's a fault in my vault! [closed]

In this game of cops and robbers, each cop will make a vault: a program that stores a secret, and requires a key to unlock. The robbers should find a way to get the vault to reveal its secret without ...
Rydwolf Programs's user avatar
45 votes
142 answers
12k views

Print X without X (robber's thread)

This is the robber's thread of a cops-and-robbers challenge. You can view the cop's thread here A pretty common beginner style question is to print some string, but, there's a catch!, you need to do ...
Wheat Wizard's user avatar
  • 98.5k