# What is the Sandbox?

This "Sandbox" is a place where Code Golf users can get feedback on prospective challenges they wish to post to the main page. This is useful because writing a clear and fully specified challenge on the first try can be difficult. There is a much better chance of your challenge being well received if you post it in the Sandbox first.

See the Sandbox FAQ for more information on how to use the Sandbox.

## Get the Sandbox Viewer to view the sandbox more easily

To add an inline tag to a proposal use shortcut link syntax with a prefix: [tag:king-of-the-hill]

Given a digit as an English word, output its numerical value.

For example, given the input one, you should output 1 (optionally with a trailing newline).

Your program should cover all the following cases:

zero  => 0
one   => 1
two   => 2
three => 3
four  => 4
five  => 5
six   => 6
seven => 7
eight => 8
nine  => 9


# Introduction

This challenge was inspired by the 24 Game.

In the 24 Game, you are given 4 numbers and are asked to make 24 using addition, subtraction, multiplication, division, and parentheses. So...

What is the biggest number you can make given 4 numbers using the above operations?

# Challenge

For four given inputs a, b, c, d, output the biggest number you can get using addition, subtraction, multiplication, division, and parentheses.

This is code-golf, so the shortest answer wins.

# Example Input and Output

  Input  -->  Output  -->   Explanation
1,3,2,4 -->    36    --> (1 + 2) × 3 × 4
5,5,5,5 -->   625    -->  5 × 5 × 5 × 5
9,2,3,1 -->    81    --> (1 + 2) × 3 × 9



Please give feedback on this challenge and correct me if my outputs are wrong. Should I change it to the smallest number?

• – FlipTack Dec 30 '19 at 23:19
• Also the subtraction and division are surely obsolete for the challenge? – FlipTack Dec 30 '19 at 23:21
• Will positive number divide zero yield Infinity as what IEEE 754 does? – tsh Dec 31 '19 at 3:37
• Shouldn't (1+2)x3x4 greater than 1+2x3x4? – tsh Dec 31 '19 at 3:37
• @FlipTack Probably but maybe not in some circumstances. – Yousername Dec 31 '19 at 22:18
• @tsh No, infinity will not count as the solution. Thank you, that is true that (1+2)x3x4 is greater. – Yousername Dec 31 '19 at 22:19
• Does order matter? From the input it seems the order matters, i.e. we are not supposed to change the order of the input. So, for 1,3,2,4, the answer is 32, rather than 36. – Element118 Jan 1 at 5:25
• @Element118 No, order does not matter, those were just the random numbers that came from my head. – Yousername Jan 4 at 21:11

# How many ACus do I have?

Posted to main

• I'm not sure this counts as a dupe, but what it seems to be is n=floor(days_between(input, date(1,1,2020)) / 7); return n*(n-1)/2, which doesn't seem terribly interesting to golf. (Also just fyi, the 01 you used in your dates in your script is actually an octal literal i.e. 010 is 8) – FryAmTheEggman Jan 7 at 21:33
• Thanks for the feedback. I have corrected the script. Not sure how the extra 0's managed to slip in! I'll leave the challenge here for a couple more days to see if there are any more comments. – ElPedro Jan 8 at 7:43
• @ElPedro You need to wait longer. At least a month or two, but a few months is really good. – S.S. Anne Jan 11 at 21:25
• I'm sorry and no personal offence intended but I find it a bit strange that a member of 3 months is telling a member of over 4 years with lot's of experience and over 5000 rep how to use the sandbox and the main site. Maybe I am simply getting too old for this community. – ElPedro Jan 11 at 21:36
• And besides which, none of that alters my opinion that downvotes without the downvoter giving a reason are not any help to anyone. If you think differently then please feel free to give me a good reason. I am happy to listen and learn. – ElPedro Jan 11 at 21:40

# Make a Decompiler Bomb

Similar to the Make a Compiler Bomb challenge, but backwards.

The goal is to create the a 1KiB (1024 bytes) or smaller bytecode file that creates the largest output when decompiled.

# Constraints

• A binary is either an x86 binary (in the form of an ELF file, PE file (.dll/.exe), or Mach-O binary) or a virtual bytecode file (e.g. Python .pyc, Java .class, .NET CLR, etc.)

• The decompiler can be any public (preferably free) decompiler of your choice. (e.g Snowman/Hex-Rays for x86 binarys, CFR/Fernflower/etc. for java, dotPeek for .NET, uncompyle6 for Python, etc.)

• A decompiler is any tool that takes a binary and attempts to reconstruct human readable source code from it.

• The largest output byte count wins, with the smallest input size as a tie-breaker

• The binary must be executable, and print "Hello World!"

• The decompiled code must be syntactically correct

• I think you probably want to specify what a "decompiler" is, since really any file is "binary" and anything that takes that and produces some valid code probably arguable counts as a decompiler. Further, I think you might be better served by limiting the binary size, like the original challenge, as if someone finds a way that adding $n$ bytes adds more than $n^{2}$ bytes to the output they would achieve an arbitrarily large score. – FryAmTheEggman Jan 17 at 20:06
• @FryAmTheEggman I put in a basic explanation and made the scoring based on largest output rather than a formula. Explaining a decompiler is tricky though, I'll think about that more and maybe edit for it later. – famous1622 Jan 21 at 14:15
• I think the scoring change you made is good, only that kb is a tad ambiguous between being 1000 or 1024, and that it seems a tad large (but neither of those is critical and the second is just my opinion). Thinking about what to do with the problem of defining a decompiler, I realised it was probably a good idea to require that the resulting decompiled code does something. Maybe requiring that the decompiled code is a hello world variant or something will limit some problems like "this program converts to Unary source code". – FryAmTheEggman Jan 21 at 16:27
• @FryAmTheEggman Made it so the decompiled code must have correct syntax, and made the size smaller, was going to post my java example but I just realized I have to make it fit in the new restrictions so... – famous1622 Jan 21 at 16:46

# I delete the input, you delete the source code

This is a new twist on the long running series on CGCC.

Your task, if you accept it, is to write a program/function that outputs/returns the contents of an input file. The tricky part is that if I delete the input file, your program must delete itself.

## Rules

• The source code file and the input file should be in the same directory.

• The input file and source file can be named anything at all. I.e. The file names are your choice.

• The contents of the input file will be restricted to printable ASCII.

• The input file and the source file must be deletable.

• This is code-golf, so the shortest (original) code in each language wins!

• Default Loopholes apply.

## Example

If your program is jspwjxnlow8229 and the input file exists, the program must print the contents of the file. If the file doesn't exist, the program must delete itself.

## Feedback

In regards to file manipulation, have I specified the rules enough?

• What about languages in which programs don't live in files but rather in binary blobs? Is it enough for the program to delete itself from the binary blob? – Adám Jan 22 at 9:30
• Can the program and/or source file also be named anything at all? – Adám Jan 22 at 9:32
• @Adam, forgive me for not knowing, but what's a binary blob? – Lyxal Jan 22 at 9:32
• It doesn't matter what a binary blob is. I just wanted you to be aware than not all languages use the same model. – Adám Jan 22 at 9:33
• @Adam sure. I'll add a part about that to the challenge – Lyxal Jan 22 at 9:34
• Parts of this feel a bit unclear. Can the submissions know the file names in advance? (If not then the name feels a bit odd, isn't it really write a cat program that deletes itself if the input name doesn't correspond to an existing file? They aren't really tied together in that case) Similarly, why mention the recycling bin? It isn't present on many systems, and behaves differently on those that do have one (most programmatic deletions will require more work to send the file to the temporary "are you sure" location). – FryAmTheEggman Jan 22 at 17:06

# How healthy are my children?

As anyone who has twins will know, it can be hard to keep track of which child fed / was changed, and when.

That's why I've devised a system using OneNote on my phone. It's quick and easy to use.

Each entry (line) uses the following structure (note: I'm not a regex expert and the expression is more permissive than I want - see words for detail):

(ddMMyyyy )?HHmm ((1|2|B) (💧|💩|🤱){1,3}){1,3}

Or, in words:

1. For the first entry on or after midnight each day only, each line starts with the date.
2. The next component is always the time, hour and minute in 24 hour clock format
3. Next is a child identifier character - 1 or 2; or B if what follows applies to both children. All subsequent emoticons apply to the identified child, until a new child identifier is found or a newline. There is guaranteed to be at least one child identifier in a record.
4. Next comes any or all of the three emoticons (maximum one of each) representing a wet nappy (💧), a dirty nappy (💩) or a feed (🤱)
5. Repeat from step 3. until done. BUT - each emoticon will only appear once per child - so if it appears in B then it won't appear in either 1 or 2; and if it appears in either 1 or 2 it won't appear in B. It won't appear in both 1 and 2 (because then it would be in B instead). The regex doesn't show this subtlety.

Some other notes:

• Breast-Feeding (feed) emoticon 🤱 is codepoint U+1F931
• Droplet (wet) emoticon 💧 is codepoint U+1F4A7
• Pile of Poo (dirty) emoticon 💩 is codepoint U+1F4A9
• All items in the string are space-separated
• I would actually use the initials of my children's names, rather than 1 and 2 - but for the challenge I went with the numbers instead.

## Example

02022020 0005 1 💩 B 💧 🤱
0230 2 💧 🤱
0250 1 💧 💩 🤱
0330 2 🤱
0400 1 🤱
0700 B 💧 🤱
0900 2 🤱
1000 2 💧 🤱
1020 1 💧 🤱
1220 1 🤱
1420 B 💧 1 💩 2 🤱
1440 1 🤱
1600 2 💧 💩
1700 1 💧
1745 B 🤱
2100 B 💧 🤱 1 💩
2350 2 🤱 B 💩 1 💧
03022020 0015 1 🤱 B 💧
0500 1 💧 🤱
0830 1 💧 🤱
0900 2 💧 🤱
1115 B 💧 1 💩
1215 B 🤱
1330 B 🤱
1400 2 💧 💩

# The Challenge

Given the raw data, input as a single string or array of entries, containing data such as the above example, output a summary of:

• number of feeds, wet and dirty nappies, per baby, over the past 24 hours

"The past 24 hours" can be either based on system time, or the current time can be passed as an extra input.

The output format is up to you, as long as it:

a) is consistent across all runs of the program
b) shows the information required

some example outputs for the above inputs, with a current time of 14:30 on 3rd of February 2020 (hand-calculated, sorry if they're not right!):

Baby 1 had 6 wet nappies, 2 dirty nappies, and fed 8 times Baby 2 had 6 wet nappies, 3 dirty nappies and fed 6 times

{{6,6},{2,3},{8,6}}

{6,2,8},{6,3,6}

etc.

This is so lowest bytes wins. Usual exclusions apply.

• If a language can't deal with unicode input, should I allow the whole codepoint string substituted in its place? – simonalexander2005 Feb 14 at 11:59
• Should I be more explicit with the output format? – simonalexander2005 Feb 14 at 12:00
• Can someone help me make the regex more tight? – simonalexander2005 Feb 14 at 12:05

I want to ask a combined popularity / objectively scored question. Something like:

Take a string as input. Match the string to a famous painting such as "Mona Lisa" and render a cartoon version of it. 1 point per painting, 1 point per upvote. Voting closes on XX/YY/ZZZZ.

I want to reward people for including more possibilities (there will be a fixed upper limit, unlike with paintings). I also want to reward people for the quality of their renderings. The cartoon paintings should be recognisable as versions of the real paintings.

Is this a good scoring system? If not, what would be better?

• This is somewhat vague. Can you be more precise? – Don Thousand Feb 17 at 15:38

# Implement PSL(2,3)

Since challenge to implement Galois field already have been many, I'm writing a challenge involving a group of Lie type!

## Objective

Implement the multiplication and inversion in $$\\text{PSL}(2,3)\$$.

## The ring $$\\mathbb{Z}_3\$$

The ring $$\\mathbb{Z}_3\$$ is the set $$\\{0,1,2\}\$$ with addition, negation, subtraction, and multiplication defined as modular arithmetic:

• Addition is the usual addition with the result moduloed by 3;

• Negation, subtraction, and multiplication are also analogously defined.

Reciprocal and division is also well-defined, but that's just another detail.

## The group $$\\text{SL}(2,3)\$$

The multiplicative group $$\\text{SL}(2,3)\$$ is the set of 2-by-2 matrices whose entries are members of $$\\mathbb{Z}_3\$$ and the determinant is $$\1\$$. Note that the determinant is calculated using modular arithmetic. Matrix multiplication and matrix inversion is defined as:

• Matrix multiplication is the usual matrix multiplication, where addition and multiplication of the entries are modular;

• Matrix inversion of $$\\begin{pmatrix} a & b \\ c & d \end{pmatrix}\$$ is $$\\begin{pmatrix} d & -b \\ -c & a \end{pmatrix}\$$. This exploits that the determinant is $$\1\$$.

As a consequence, the elements of $$\\text{SL}(2,3)\$$ are:

$$\begin{pmatrix} 0 & 1 \\ 2 & 0\end{pmatrix}, \begin{pmatrix} 0 & 1 \\ 2 & 1\end{pmatrix}, \begin{pmatrix} 0 & 1 \\ 2 & 2\end{pmatrix}, \begin{pmatrix} 0 & 2 \\ 1 & 0\end{pmatrix}, \begin{pmatrix} 0 & 2 \\ 1 & 1\end{pmatrix}, \begin{pmatrix} 0 & 2 \\ 1 & 2\end{pmatrix}, \begin{pmatrix} 1 & 0 \\ 0 & 1\end{pmatrix}, \begin{pmatrix} 1 & 0 \\ 1 & 1\end{pmatrix}, \begin{pmatrix} 1 & 0 \\ 2 & 1\end{pmatrix}, \begin{pmatrix} 1 & 1 \\ 0 & 1\end{pmatrix}, \begin{pmatrix} 1 & 1 \\ 1 & 2\end{pmatrix}, \begin{pmatrix} 1 & 1 \\ 2 & 0\end{pmatrix}, \begin{pmatrix} 1 & 2 \\ 0 & 1\end{pmatrix}, \begin{pmatrix} 1 & 2 \\ 1 & 0\end{pmatrix}, \begin{pmatrix} 1 & 2 \\ 2 & 2\end{pmatrix}, \begin{pmatrix} 2 & 0 \\ 0 & 2\end{pmatrix}, \begin{pmatrix} 2 & 0 \\ 1 & 2\end{pmatrix}, \begin{pmatrix} 2 & 0 \\ 2 & 2\end{pmatrix}, \begin{pmatrix} 2 & 1 \\ 0 & 2\end{pmatrix}, \begin{pmatrix} 2 & 1 \\ 1 & 1\end{pmatrix}, \begin{pmatrix} 2 & 1 \\ 2 & 0\end{pmatrix}, \begin{pmatrix} 2 & 2 \\ 0 & 2\end{pmatrix}, \begin{pmatrix} 2 & 2 \\ 1 & 0\end{pmatrix}, \begin{pmatrix} 2 & 2 \\ 2 & 1\end{pmatrix}$$

## The factor group $$\\text{PSL}(2,3)\$$

$$\\text{PSL}(2,3)\$$ is defined as cosets of $$\\text{SL}(2,3)\$$ by $$\\{\begin{pmatrix} 1 & 0 \\ 0 & 1\end{pmatrix}, \begin{pmatrix} 2 & 0 \\ 0 & 2\end{pmatrix}\}\$$. That is, elementwise multiplications of $$\\{\begin{pmatrix} 1 & 0 \\ 0 & 1\end{pmatrix}, \begin{pmatrix} 2 & 0 \\ 0 & 2\end{pmatrix}\}\$$. They are: $$\{\begin{pmatrix} 0 & 1 \\ 2 & 0\end{pmatrix}, \begin{pmatrix} 0 & 2 \\ 1 & 0\end{pmatrix}\}, \{\begin{pmatrix} 0 & 1 \\ 2 & 1\end{pmatrix}, \begin{pmatrix} 0 & 2 \\ 1 & 2\end{pmatrix}\}, \{\begin{pmatrix} 0 & 1 \\ 2 & 2\end{pmatrix}, \begin{pmatrix} 0 & 2 \\ 1 & 1\end{pmatrix}\}, \{\begin{pmatrix} 1 & 0 \\ 0 & 1\end{pmatrix}, \begin{pmatrix} 2 & 0 \\ 0 & 2\end{pmatrix}\}, \{\begin{pmatrix} 1 & 0 \\ 1 & 1\end{pmatrix}, \begin{pmatrix} 2 & 0 \\ 2 & 2\end{pmatrix}\}, \{\begin{pmatrix} 1 & 0 \\ 2 & 1\end{pmatrix}, \begin{pmatrix} 2 & 0 \\ 1 & 2\end{pmatrix}\}, \{\begin{pmatrix} 1 & 1 \\ 0 & 1\end{pmatrix}, \begin{pmatrix} 2 & 2 \\ 0 & 2\end{pmatrix}\}, \{\begin{pmatrix} 1 & 1 \\ 1 & 2\end{pmatrix}, \begin{pmatrix} 2 & 2 \\ 2 & 1\end{pmatrix}\}, \{\begin{pmatrix} 1 & 1 \\ 2 & 0\end{pmatrix}, \begin{pmatrix} 2 & 2 \\ 1 & 0\end{pmatrix}\}, \{\begin{pmatrix} 1 & 2 \\ 0 & 1\end{pmatrix}, \begin{pmatrix} 2 & 1 \\ 0 & 2\end{pmatrix}\}, \{\begin{pmatrix} 1 & 2 \\ 1 & 0\end{pmatrix}, \begin{pmatrix} 2 & 1 \\ 2 & 0\end{pmatrix}\}, \{\begin{pmatrix} 1 & 2 \\ 2 & 2\end{pmatrix}, \begin{pmatrix} 2 & 1 \\ 1 & 1\end{pmatrix}\},$$

You pick an element of each coset as representives, and don't care about the rest.

Multiplication/inversion of such representives is defined as multiplication/inversion in $$\\text{SL}(2,3)\$$, then taking the representive of the coset the multiplication/inversion is in. For example, $$\\begin{pmatrix} 0 & 1 \\ 2 & 0\end{pmatrix}^2 = \begin{pmatrix} 1 & 0 \\ 0 & 1\end{pmatrix}\$$, if $$\\begin{pmatrix} 0 & 1 \\ 2 & 0\end{pmatrix}\$$ and $$\\begin{pmatrix} 1 & 0 \\ 0 & 1\end{pmatrix}\$$ are representives.

## Examples

Picking the left elements as representives of the cosets above: $$\begin{pmatrix} 0 & 1 \\ 2 & 0\end{pmatrix}^2 = \begin{pmatrix} 1 & 0 \\ 0 & 1\end{pmatrix}, \begin{pmatrix} 0 & 1 \\ 2 & 1\end{pmatrix}^2 = \begin{pmatrix} 1 & 2 \\ 1 & 0\end{pmatrix}, \begin{pmatrix} 1 & 0 \\ 0 & 1\end{pmatrix}\begin{pmatrix} 1 & 1 \\ 1 & 2\end{pmatrix} = \begin{pmatrix} 1 & 1 \\ 1 & 2\end{pmatrix}, \begin{pmatrix} 1 & 2 \\ 2 & 2\end{pmatrix}\begin{pmatrix} 1 & 1 \\ 1 & 2\end{pmatrix} = \begin{pmatrix} 0 & 1 \\ 2 & 0\end{pmatrix}, \begin{pmatrix} 1 & 2 \\ 2 & 2\end{pmatrix}^{-1} = \begin{pmatrix} 1 & 2 \\ 2 & 2\end{pmatrix}$$ To be more specific about the method of evaluation: $$\begin{pmatrix} 0 & 1 \\ 2 & 1\end{pmatrix}\begin{pmatrix} 0 & 1 \\ 2 & 2\end{pmatrix} ≡ \begin{pmatrix} 2 & 2 \\ 2 & 4\end{pmatrix} ≡ \begin{pmatrix} 2 & 2 \\ 2 & 1\end{pmatrix} ≡ \begin{pmatrix} 1 & 1 \\ 1 & 2\end{pmatrix}, \\ \begin{pmatrix} 1 & 1 \\ 1 & 2\end{pmatrix}^{-1} ≡ \begin{pmatrix} 2 & -1 \\ -1 & 1\end{pmatrix} ≡ \begin{pmatrix} 2 & 2 \\ 2 & 1\end{pmatrix} ≡ \begin{pmatrix} 1 & 1 \\ 1 & 2\end{pmatrix}$$ The steps of this algorithm is:

1. Do usual matrix multiplication/inversion;
2. Modulo the entries by 3;
3. Take the representive of the coset.

Though you can make any possible algorithm.

## Rules

• Input type and format doesn't matter, but it must be a container of integers. In C, int[2][2] and int[4] are valid examples. This restriction prevents abusing the fact that $$\\text{PSL}(2,3) \cong A_4\$$.
• Output type and format doesn't matter either, but it must be the same as the input type and format.
• Invalid inputs fall in don't care situation.
• Multiplication and inversion may be in separate codes. In this case, the score is the sum of their lengths in bytes.
• Since this is a code-golf, the code with least score wins.
• This challenge appears to heavily rely on restricted-source and thus to me does not seem too viable. – Jonathan Frech Feb 25 at 0:58
• @JonathanFrech Do you think I should lift the restriction on input type? Otherwise, "You pick an element of each coset as representives, and don't care about the rest" and "Invalid inputs fall in don't care situation" should be enough. – Dannyu NDos Feb 25 at 3:38

## Very rough outline of a challenge that rewards short programs that take a long time.

Probably a no input and output can be anything except an error challenge.

Is there a nice way to exclude things like sleep(), wait() etc?

Would be required for 1 person to run all the programs for the timing to be fair.

Thinking that answers would include loops, recursion, testing of complex criteria.

• I think you would have to post your challenge as a popularity contest ... a slippery slope indeed. – Jonathan Frech Mar 15 at 23:43

## Design a Stack With Increment Operation

Design a stack that supports the following operations.

Implement the CustomStack class:

• CustomStack(int maxSize) Initializes the object with maxSize which is the maximum number of elements in the stack or do nothing if the stack reached the maxSize.
• void push(int x) Adds x to the top of the stack if the stack hasn't reached the maxSize.
• int pop() Pops and returns the top of stack or -1 if the stack is empty.
• void inc(int k, int val) Increments the bottom k elements of the stack by val. If there are less than k elements in the stack, just increment all the elements in the stack.

### Test Case:

Input

["CustomStack","push","push","pop","push","push","push","increment","increment","pop","pop","pop","pop"]
[[3],[1],[2],[],[2],[3],[4],[5,100],[2,100],[],[],[],[]]

Output

[null,null,null,2,null,null,null,null,null,103,202,201,-1]

Explanation

CustomStack customStack = new CustomStack(3); // Stack is Empty []
customStack.push(1);                          // stack becomes [1]
customStack.push(2);                          // stack becomes [1, 2]
customStack.pop();                            // return 2 --> Return top of the stack 2, stack becomes [1]
customStack.push(2);                          // stack becomes [1, 2]
customStack.push(3);                          // stack becomes [1, 2, 3]
customStack.push(4);                          // stack still [1, 2, 3], Don't add another elements as size is 4
customStack.increment(5, 100);                // stack becomes [101, 102, 103]
customStack.increment(2, 100);                // stack becomes [201, 202, 103]
customStack.pop();                            // return 103 --> Return top of the stack 103, stack becomes [201, 202]
customStack.pop();                            // return 202 --> Return top of the stack 102, stack becomes [201]
customStack.pop();                            // return 201 --> Return top of the stack 101, stack becomes []
customStack.pop();                            // return -1 --> Stack is empty return -1.


This is code-golf so shortest submission in bytes wins! If you liked this challenge, consider upvoting it... And happy golfing!

• This would be limited to Java and C++. I could almost guarantee that this will be downvoted and closed as unclear if posted. – S.S. Anne Mar 15 at 15:45
• I agree with @S.S.Anne; terms like class, void and even the concept of operations are not existent in a majority of languages. – Jonathan Frech Mar 15 at 23:35
• One possibility of altering the challenge may be to supply a finite number of stack instructions as a series of text commands and ask how the stack looks at the end ... Kind of asking to implement an interpreter for a basic stack-based language. – Jonathan Frech Mar 15 at 23:36

## Find the longest common subsequence

Given two integer arrays. Find the longest common subsequence

Test Case:

Input:

a=[1,5,2,6,3,7]
b=[5,6,7,1,2,3]


Output:

Return
[1,2,3] or [5,6,7]


This is code-golf so shortest submission in bytes wins! If you liked this challenge, consider upvoting it... And happy golfing!

• Similar to this challenge. – Jonathan Frech Mar 15 at 23:29
• @JonathanFrech Yeah Similar, But not Same. Am I supposed to post the challenge?? – Pluviophile Mar 17 at 15:52
• Posting is up to you. I would not, since I think it would be righteously closed as a duplicate. – Jonathan Frech Mar 17 at 16:27

# The (All But) Quine challenge

Like a quine challenge, but the opposite. Print everything except source code

# Challenge

Write a program, which takes no input, and outputs all the strings of printable characters which are the same length as the source code of the program, except the source code of the program.

# Scoring

The shortest program (per language) to accomplish the above task, wins

• By 'printable characters' you mean printable ASCII characters (code-points [32,126])? What if I use a language that don't contain any ASCII characters in its source code? – Kevin Cruijssen Mar 20 at 13:38
• If your program is in ASCII, then you would need to print all of the ASCII characters, if the program is in Unicode, then you would have to print all of the Unicode characters – Benji Mar 20 at 14:40
• @Benji Would you consider a Python 3 source file as being "in Unicode"? – Jonathan Frech Mar 22 at 17:49
• If there are any Unicode characters that are used in the file, then no. If Unicode characters are used, then I would consider it to be Unicode – Benji Mar 23 at 14:47

## Maximum Performance of a Team

There are $$\n\$$ engineers numbered from 1 to $$\n\$$ and two arrays: speed and efficiency, where $$\speed[i]\$$ and $$\efficiency[i]\$$ represent the speed and efficiency for the i-th engineer respectively. Return the maximum performance of a team composed of at most $$\k\$$ engineers, since the answer can be a huge number, return this modulo $$\10^9 + 7.\$$

The performance of a team is the sum of their engineers' speeds multiplied by the minimum efficiency among their engineers.

Test Case 1:

Input: n = 6, speed = [2,10,3,1,5,8], efficiency = [5,4,3,9,7,2], k = 2

Output: 60


Explanation:

We have the maximum performance of the team by selecting engineer 2 (with speed=10 and efficiency=4) and engineer 5 (with speed=5 and efficiency=7). That is, performance = $$$$10 + 5) * min(4, 7) = 60.\$$ Test Case 2: Input: n = 6, speed = [2,10,3,1,5,8], efficiency = [5,4,3,9,7,2], k = 3 Output: 68  Explanation: This is the same example as the first but k = 3. We can select engineer 1, engineer 2 and engineer 5 to get the maximum performance of the team. That is, performance = $$\(2 + 10 + 5) * min(5, 4, 7) = 68.\$$ Test Case 3: Input: n = 6, speed = [2,10,3,1,5,8], efficiency = [5,4,3,9,7,2], k = 4 Output: 72  Please feel free to add more test cases. This is code-golf so shortest submission in bytes wins! If you liked this challenge, consider upvoting it... And happy golfing! • Since this is a challenge from another site, I don't think you'd be allowed to post it here without express permission. – xnor Mar 19 at 16:38 ## Numbers by index Challenge Print the numbers: 0 1 22 333 4444 55555 666666 7777777 88888888 999999999  In that order. I/O Takes no input. The numbers can have any delimiters desired (or none). Example outputs: 0122333444455555666666777777788888888999999999 [0,1,22,333,4444,55555,666666,7777777,88888888,999999999] etc....  Code Example This is an un-golfed example that may perhaps act as algorithm guide (or maybe not): # Turing Machine Code, 553 bytes 0 * 0 r K K * _ r 1 1 * 1 r L L * _ r 2 2 * 2 r a a * 2 r M M * _ r 3 3 * 3 r b b * 3 r c c * 3 r N N * _ r 4 4 * 4 r d d * 4 r e e * 4 r f f * 4 r O O * _ r 5 5 * 5 r g g * 5 r h h * 5 r i i * 5 r j j * 5 r P P * _ r 6 6 * 6 r k k * 6 r l l * 6 r m m * 6 r n n * 6 r o o * 6 r Q Q * _ r 7 7 * 7 r p p * 7 r q q * 7 r r r * 7 r s s * 7 r t t * 7 r u u * 7 r R R * _ r 8 8 * 8 r v v * 8 r w w * 8 r x x * 8 r y y * 8 r z z * 8 r A A * 8 r B B * 8 r S S * _ r 9 9 * 9 r C C * 9 r D D * 9 r E E * 9 r F F * 9 r G G * 9 r H H * 9 r I I * 9 r J J * 9 r halt  Try it online! This prints out the numbers with a space delimiter: 0 1 22 333 4444 55555 666666 7777777 88888888 999999999  Challenge Type , so shortest answer in bytes (by language) wins. Edit: Link to the related challenge. Curiously, there is one answer on there where if it was by index, and the zero was included, it would be shorter. • Nice challenge! Are preceding & trailing whitespace (during string output) permitted? – user92069 Mar 11 at 3:22 • I think it should also be kolgomorov-complexity. – PkmnQ Mar 11 at 5:19 • I don't like how the zero breaks the pattern of having the digit N appear N times -- it seems like an exceptional edge case. I think it would be better for 0 not to appear, so the numbers would just start from 1. – xnor Mar 11 at 7:06 • @xnor, I knew you wouldn't like it (and probably a few other won't as well) That's on purpose. It just seems a little too easy otherwise. – ouflak Mar 11 at 7:28 • @a'_', Yes. @ PkmnQ, Noted. – ouflak Mar 11 at 7:29 • I don't really see how adding a fixed zero to the beginning makes the challenge harder in almost any language. In some, the empty string will actually convert to zero, which makes it more natural but still fairly trivial. I feel like you probably either want to go with omitting the zero, or finding a different way to make the challenge more complicated. – FryAmTheEggman Mar 11 at 14:53 • @FryAmTheEggman, How can you have a challenge about indexes and not have zero? That just seems wrong. – ouflak Mar 11 at 15:31 • Most people start counting from one - only people who use computers a lot default to starting at zero. And separately, I think finding another way to incorporate it is better than leaving it out (I just also think both are better than having an unexplained outlier). – FryAmTheEggman Mar 11 at 15:40 • @FryAmTheEggman, But it's not really unexplained is it? It's the index of the first number. – ouflak Mar 11 at 15:46 • As per what xnor said, it doesn't match the pattern of the others. That behaviour is not explained. Comments aren't really for a discussion like this; if you disagree that is fine. I've just given feedback on how I think you could improve the challenge. – FryAmTheEggman Mar 11 at 16:15 • I do want to make sure that everyone knows that I am VERY grateful for the feedback! I also appreciate having a Sandbox where we can have this discussion here instead of on the main site. – ouflak Mar 11 at 16:18 • @FryAmTheEggman, It's not that I disagree. I kind of agree. I like that leading zero in there to represent the index location of the initial value. I considered this when I thought of the question, before posting it here. It breaks up a trivial loop sequence answer a bit, or maybe even inspires a clever solution that nobody considered. I'd like to keep it because it stands out like that, not despite that. – ouflak Mar 11 at 16:21 • I posted an example implementation above. The zero wasn't a big deal. – ouflak Mar 11 at 16:31 • My guess is that you're excited about the arithmetic expression 10**n/9*n or similar. But I don't think that's much more interesting than the obvious loops that removing the zero would allow unmodified. – xnor Mar 11 at 21:59 • @ouflak I contrast, I am very excited about arithmetic expressions :) – xnor Mar 12 at 21:16 # A malbolge interpreter The challenge today is to write a Malbolge interpreter. ## Specification Malbolge '98, Ben Olmstead I hereby relenquish any and all copyright on this language, documentation, and interpreter; Malbolge is officially public domain. ------------------------------------------------------------------------ Malbolge '98, Ben Olmstead Introduction ^^^^^^^^^^^^ It was noticed that, in the field of esoteric programming languages, there was a particular and surprising void: no programming language known to the author was specifically designed to be difficult to program in. Certainly, there were languages which were difficult to write in, and far more were difficult to read (see: Befunge, False, TWDL, RUBE...). But even INTERCAL and BrainF***, the two kings of mental torment, were designed with other goals: INTERCAL to have nothing in common with any major programming language, and BrainF*** to be a very tiny, yet still Turing-complete, language. INTERCAL's constructs are certainly tortuous, but they are all too flexible; you can, for instance, quite easily assign any number to a variable with a single statement. BrainF*** is lacking the flexibility which is INTERCAL's major weakness, but it fails in that its constructs are far, far too intuitive. Certainly, there are only 8 instructions, none of which take any arguments--but it is quite easy to determine how to use those instructions. Subtract 8 from the current number? With a simple '--------' you are done! This kind of simple answer was unacceptable to the author. Hence the author created Malbolge. It borrows from machine, BrainF***, and tri-INTERCAL, but put together in a unique way. It was designed to be difficult to use, and so it is. It is designed to be incomprehensible, and so it is. So far, no Malbolge programs have been written. Thus, we cannot give an example. "Malbolge" is the name of Dante's Eighth Circle of Hell, in which practitioners of deception (seducers, flatterers, simonists, thieves, hypocrites, and so on) spend eternity. Environment ^^^^^^^^^^^ In many languages, the environment is easy to understand. In Malbolge, it is best to understand the runtime environment before you ever see a command. The environment is, roughly, that of a primitive trinary CPU. Both code and data share the same space (the machine's memory segment), and there are three registers. Machine words are ten trits (trinary digits) wide, giving a maximum possible value of 59048 (all numbers are unsigned). Memory space is exactly 59049 words long. The three registers are A, C, and D. A is the accumulator, used for data manipulation. A is implicitly set to the value written by all write operations on memory. (Standard I/O, a distinctly non-chip-level feature, is done directly with the A register.) C is the code pointer. It is automatically incremented after each instruction, and points the instruction being executed. D is the data pointer. It, too, is automatically incremented after each instruction, but the location it points to is used for the data manipulation commands. All registers begin with the value 0. When the interpreter loads the program, it ignores all whitespace. If it encounters anything that is not one of an instruction and is not whitespace, it will give an error, otherwise it loads the file, one non- whitespace character per cell, into memory. Cells which are not initialized are set by performing op on the previous two cells repetitively. Commands ^^^^^^^^ When the interpreter tries to execute a program, it first checks to see if the current instruction is a graphical ASCII character (33 through 126). If it is, it subtracts 33 from it, adds C to it, mods it by 94, then uses the result as an index into the following table of 94 characters: +b(29e*j1VMEKLyC})8&m#~W>qxdRp0wkrUo[D7,XTcA"lI .v%{gJh4G\-=O@5_3i<?Z';FNQuY]szf!BS/|t:Pn6^Ha It then checks it against the characters listed below, and performs an appropriate action. If the result is not one of the characters listed below, it is treated as a nop. If the original character is not graphic ASCII, the program is immediately ended. When the interpreter parses the input file, it checks each non- whitespace character with the process above. If any result is not one of the eight characters below, the file will be rejected. After the instruction is executed, 33 is subtracted from the instruction at C, and the result is used as an index in the table below. The new character is then placed at C, and then C is incremented. 5z]&gqtyfr(we4{WP)H-Zn,[%\3dL+Q;>U!pJS72FhOA1C B6v^=I_0/8|jsb9m<.TVacuY*MK'X~xDl}REokN:#?G"i@ j sets the data pointer to the value in the cell pointed to by the current data pointer. i sets the code pointer to the value in the cell pointed to be the current data pointer. * rotates the trinary value of the cell pointed to by D to the right 1. The least significant trit becomes the most significant trit, and all others move one position to the left. p performs a tritwise "op" on the value pointed to by D with the contents of A. The op (don't look for pattern, it's not there) is: | A trit: ________|_0__1__2_ 0 | 1 0 0 *D 1 | 1 0 2 trit 2 | 2 2 1 Di-trits: 00 01 02 10 11 12 20 21 22 00 04 03 03 01 00 00 01 00 00 01 04 03 05 01 00 02 01 00 02 02 05 05 04 02 02 01 02 02 01 10 04 03 03 01 00 00 07 06 06 11 04 03 05 01 00 02 07 06 08 12 05 05 04 02 02 01 08 08 07 20 07 06 06 07 06 06 04 03 03 21 07 06 08 07 06 08 04 03 05 22 08 08 07 08 08 07 05 05 04 < reads an ASCII value from the stdin and converts it to Trinary, then stores it in A. 10 (line feed) is considered 'newline', and 2222222222t (59048 dec.) is EOF. / converts the value in A to ASCII and writes it to stdout. Writing 10 is a newline. v indicates a full stop for the machine. o does nothing, except increment C and D, as all other instructions do. Turing-Completeness ^^^^^^^^^^^^^^^^^^^ Though I have not proven it, I _think_ Malbolge to be Turing-complete. To be Turing-complete, there must be some data construct which can be used to do any mathematical calculation. I believe that using *p in various clever ways on the tritwords can fulfill this requirement. Turing-completeness also requires three code constructs: sequential execution (which Malbolge obviously has), repetition (provided by the i and, indirectly, j instructions), and conditional-execution (provided, I believe, by self-modifying code and altering i destinations). I do have my doubts, particularly about data constructs, but I *think* this works... Appendix: Trinary Conversion Table ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Trinary to ASCII to decimal to hex table, provided, strangely enough, for the convenience of Malbolge programmers. 00000 NUL 000 00 01012 032 20 02101 @ 064 40 10120  096 60 00001 SOH 001 01 01020 ! 033 21 02102 A 065 41 10121 a 097 61 00002 STX 002 02 01021 " 034 22 02110 B 066 42 10122 b 098 62 00010 ETX 003 03 01022 # 035 23 02111 C 067 43 10200 c 099 63 00011 EOT 004 04 01100  036 24 02112 D 068 44 10201 d 100 64 00012 ENQ 005 05 01101 % 037 25 02120 E 069 45 10202 e 101 65 00020 ACK 006 06 01102 & 038 26 02121 F 070 46 10210 f 102 66 00021 BEL 007 07 01110 ' 039 27 02122 G 071 47 10211 g 103 67 00022 BS 008 08 01111 ( 040 28 02200 H 072 48 10212 h 104 68 00100 HT 009 09 01112 ) 041 29 02201 I 073 49 10220 i 105 69 00101 LF 010 0a 01120 * 042 2a 02202 J 074 4a 10221 j 106 6a 00102 VT 011 0b 01121 + 043 2b 02210 K 075 4b 10222 k 107 6b 00110 FF 012 0c 01122 , 044 2c 02211 L 076 4c 11000 l 108 6c 00111 CR 013 0d 01200 - 045 2d 02212 M 077 4d 11001 m 109 6d 00112 SO 014 0e 01201 . 046 2e 02220 N 078 4e 11002 n 110 6e 00120 SI 015 0f 01202 / 047 2f 02221 O 079 4f 11010 o 111 6f 00121 DLE 016 10 01210 0 048 30 02222 P 080 50 11011 p 112 70 00122 DC1 017 11 01211 1 049 31 10000 Q 081 51 11012 q 113 71 00200 DC2 018 12 01212 2 050 32 10001 R 082 52 11020 r 114 72 00201 DC3 019 13 01220 3 051 33 10002 S 083 53 11021 s 115 73 00202 DC4 020 14 01221 4 052 34 10010 T 084 54 11022 t 116 74 00210 NAK 021 15 01222 5 053 35 10011 U 085 55 11100 u 117 75 00211 SYN 022 16 02000 6 054 36 10012 V 086 56 11101 v 118 76 00212 ETB 023 17 02001 7 055 37 10020 W 087 57 11102 w 119 77 00220 CAN 024 18 02002 8 056 38 10021 X 088 58 11110 x 120 78 00221 EM 025 19 02010 9 057 39 10022 Y 089 59 11111 y 121 79 00222 SUB 026 1a 02011 : 058 3a 10100 Z 090 5a 11112 z 122 7a 01000 ESC 027 1b 02012 ; 059 3b 10101 [ 091 5b 11120 { 123 7b 01001 FS 028 1c 02020 < 060 3c 10102 \ 092 5c 11121 | 124 7c 01002 GS 029 1d 02021 = 061 3d 10110 ] 093 5d 11122 } 125 7d 01010 RS 030 1e 02022 > 062 3e 10111 ^ 094 5e 11200 ~ 126 7e 01011 US 031 1f 02100 ? 063 3f 10112 _ 095 5f 11202 128 80 12221 160 a0 21010 192 c0 22022 224 e0 11210 129 81 12222 161 a1 21011 193 c1 22100 225 e1 11211 130 82 20000 162 a2 21012 194 c2 22101 226 e2 11212 131 83 20001 163 a3 21020 195 c3 22102 227 e3 11220 132 84 20002 164 a4 21021 196 c4 22110 228 e4 11221 133 85 20010 165 a5 21022 197 c5 22111 229 e5 11222 134 86 20011 166 a6 21100 198 c6 22112 230 e6 12000 135 87 20012 167 a7 21101 199 c7 22120 231 e7 12001 136 88 20020 168 a8 21102 200 c8 22121 232 e8 12002 137 89 20021 169 a9 21110 201 c9 22122 233 e9 12010 138 8a 20022 170 aa 21111 202 ca 22200 234 ea 12011 139 8b 20100 171 ab 21112 203 cb 22201 235 eb 12012 140 8c 20101 172 ac 21120 204 cc 22202 236 ec 12020 141 8d 20102 173 ad 21121 205 cd 22210 237 ed 12021 142 8e 20110 174 ae 21122 206 ce 22211 238 ee 12022 143 8f 20111 175 af 21200 207 cf 22212 239 ef 12100 144 90 20112 176 b0 21201 208 d0 22220 240 f0 12101 145 91 20120 177 b1 21202 209 d1 22221 241 f1 12102 146 92 20121 178 b2 21210 210 d2 22222 242 f2 12110 147 93 20122 179 b3 21211 211 d3 12111 148 94 20200 180 b4 21212 212 d4 12112 149 95 20201 181 b5 21220 213 d5 12120 150 96 20202 182 b6 21221 214 d6 12121 151 97 20210 183 b7 21222 215 d7 12122 152 98 20211 184 b8 22000 216 d8 12200 153 99 20212 185 b9 22001 217 d9 12201 154 9a 20220 186 ba 22002 218 da 12202 155 9b 20221 187 bb 22010 219 db 12210 156 9c 20222 188 bc 22011 220 dc 12211 157 9d 21000 189 bd 22012 221 dd 12212 158 9e 21001 190 be 22020 222 de 12220 159 9f 21002 191 bf 22021 223 df  ## Notes Note that the original specification has one quirk: after encountering an illegal instruction, the interpreter hangs. You may choose which behaviour do you want to implement (hang or exit). ## I/O rules The program or function has to take input in any reasonable way (for the program), and somehow supply the input and output features to the malbolge program (either by return value / parameter, tty or a file). ## Sandbox stuff note: I'm a bit unsure about the scoring criterion: would popularity-contest be good? I'm mostly looking for creative answers • add interpreter ? – Wezl Apr 30 at 22:00 • I think popularity-contest would be adding Do X creatively to an already relatively non-interesting challenge [unless if you somehow managed to create a Malbolge self-interpreter and that is the trick you're planning to use to win your own competition with it :) ] – the default. May 1 at 2:15 • hmm right; I'm not planning on submitting a malbolge interpreter on malbolge :P, I'd like to see what people can think of. Also I've been thinking about fastest-code contest that would possibly allow me to switch my tolling a bit :P – Kamila Szewczyk May 1 at 10:54 • I'd probably participate if this was [fastest-code], but I doubt there are enough interesting optimizations here. – the default. May 2 at 3:26 • there is a lot of room for optimization, you just need to investigate the challenge a little bit further – Kamila Szewczyk May 2 at 17:46 Write two programs (likely functions since IO for float convert to/from stream, losing info as mentioned later), one given $$\n\geq 2\$$ real points on a 2D plane, returning $$\2n-3\$$ real numbers; another given the $$\2n-3\$$ real numbers, return the same shape and size given to first program. Order of points matters. Returning a mirrored shape is fine. You must use an in-language float and assume it is infinitely precise, but converting to types like string or trying to handle the bits in RAM truncate the precision. There's no requirements on how you map, so you can even just pack some real numbers into one if your language happens to have way to do that. • Should the last sentence be "you can't"? – user202729 Jun 16 at 11:43 • Is the rotation (orientation) important? (if it doesn't, I assume that it's possible to use 2n-4 real numbers?) – user202729 Jun 16 at 11:44 • @user202729 Rotation not important, size important. You are allowed if able, but as I know no language do that – l4m2 Jun 16 at 12:38 • But it's not an observable behavior (although there's no built-in for it, it's possible to simply interleave the digits, while it's not possible to do it in finite time for irrational floating point numbers -- alternatively you can assume that only coordinates with finite binary representation are valid input). You can require that the mapping is (almost everywhere) continuous, however. – user202729 Jun 16 at 13:26 • Can I use multiple floating point types in a language (e.g. float and double in C)? – Bubbler Jun 17 at 3:39 • @Bubbler What may it be used to? – l4m2 Jun 17 at 6:33 • Combine two floats into a double at the bit level. – Bubbler Jun 17 at 6:49 • @Bubbler It'll likely result in nan – l4m2 Jun 17 at 6:54 • No, simple concatenation of two floats (not a NaN or Infinity) is guaranteed to give a value that is neither NaN nor Infinity. cf. Single, Double – Bubbler Jun 17 at 7:12 • @Bubbler Anyway now doing such lose precision – l4m2 Jun 17 at 7:15 • OK, that would work. – Bubbler Jun 17 at 7:19 • (you didn't answer my last question.) – user202729 Jun 17 at 10:16 • @user202729 How 2n-4? – l4m2 Jun 17 at 10:34 • No, the latter question about unobservable behavior. – user202729 Jun 17 at 10:59 • @user202729 What does the it refer? – l4m2 Jun 17 at 11:29 # What day is it today? atomic-code-golf Given a date y4y3y2y1-m2m1-d2d1, output the day in the week w. 0 as Sunday, 1 as Monday, and so on. You can assume the date is valid, and we use the current date rule and leap rule. Each submission should be written in this specific programming language: • A program consists of a mapping from string of digits to digits, and a sequence of instructions. • Each instruction has the format: var=[var|dgt],[var|dgt],...,[var|dgt], which assigns the value of looking up the string constructed by concatenating the values of the right hand side elements ([var|dgt],[var|dgt],...,[var|dgt]) together in the table and put it into the var on the left. A program is valid if: • None of the lookup step fails for all valid input date. • Given any valid date in the format mentioned above (initially assigned to the 8 variables y4 y3 y2 y1 m2 m1 d2 d1), after the program is run, the correct result is assigned to the variable w. You can create as many variables as you like(though bounded by amount of instructions), each variable only containing a digit. Solution win if there's no strictly better solution, aka. no solution that take less or same amount of items in mapping table, less or same amount of instrucions, and at least one of amounts of items and instructions is less. For example, this is a solution that wins: # 3652425 items 1 instruction 003000101 -> 6 003000102 -> 0 003000103 -> 1 ... 993991231 -> 5 ------------- w=y4,y3,3,y2,y1,m2,m1,d2,d1  Here, the 3 on 3rd position can be used without any extra cost. This can be used to create multiple mappings, and sometimes save elements when there are more mapping instructions. A checker is provided here. • I completely don't understand the entire You can have a mapping table and some instructions, each instruction write var=[var|dgt],[var|dgt],...,[var|dgt], meaning search the element [var|dgt],[var|dgt],...,[var|dgt]from table and put i into the var on the left. Failure on searching is not allowed. You can create as many variables as you like(though bounded by amount of instructions), each variable only containing a digit. part. – the default. Jun 15 at 8:32 • I'm very confused about this. Are you sure you're not making assumptions about language features? – Adám Jun 15 at 8:32 • @Adám I'm requiring using only this language – l4m2 Jun 15 at 8:40 • @mypronounismonicareinstate That mainly mean the only operation is lookup, there's nothing like plus, multiply or whatever – l4m2 Jun 15 at 8:41 • @l4m2 I still do not understand a word. The whole proposal definitely requires a serious rewrite. – the default. Jun 15 at 8:42 • @mypronounismonicareinstate If it hadn't needed some more time it isn't here – l4m2 Jun 15 at 8:45 • "Solution win if there's no strictly better solution" is not a valid winning criterion because it allows multiple winners. – Bubbler Jun 15 at 9:23 • @Bubbler Multiple winners is common – l4m2 Jun 15 at 9:34 • @l4m2 Do you mean something like ties in code golf? IMO, code golf ties are fine because they can be seen as equally good, while your criterion is not because it allows potentially multiple answers that can't be compared to each other at all. – Bubbler Jun 15 at 9:44 • @Bubbler I mean like multiple languages each only comparing to self – l4m2 Jun 15 at 9:50 • @l4m2 The winning criterion is the guide to optimize one's solution in one direction. "Shortest solution in each language wins" does not harm this spirit. Yours don't give which one to optimize for: mapping table size or instruction size? – Bubbler Jun 15 at 10:05 • @Bubbler Your link claims you wrong – l4m2 Jun 15 at 11:59 • @l4m2 OK, let me say it in a different way. You already showed a "winning" solution with minimal instructions. Then there will be a "winning" solution with minimal table, and then there can be thousands of "winning" solutions in between. Given any "winning" solution, one can tweak a little to get another "winning" solution. Do you really think it is fun? – Bubbler Jun 15 at 23:02 • @Bubbler Yea an exact bound of table size for each instruction count, if exist, makes its sense – l4m2 Jun 16 at 5:06 • @Bubbler You don't like to see lots of winners because you think "win" is a big issue? – l4m2 Jun 16 at 5:06 # Natural Language Identification Using Only Regular Expressions For example: const regex = /English(?=\w+ Hello World)|Spanish(?= Hola Mundo)/; console.log('EnglishSpanish Hello World'.match(regex)); // English console.log('EnglishSpanish Hola Mundo'.match(regex)); // Spanish These wordlists are to be used, and words are to be rewritten entirely using the ASCII characters A-Z and a-z. Languages which use characters that cannot be easily transcribed into ASCII without special knowledge or firsthand experience in that language, are excluded. For instance, the Albanian word të is easily transcribed without special knowledge as te, so Albanian is allowed. But the Arabic word من cannot be, so Arabic is excluded. The regular expression must match the language exactly, so appending a list of all languages you are testing before each word is allowed. But however you organize this list, it must be the same for every word you test. See the example above for clarification. ## Sandbox Questions Ideally, brevity of regex, accuracy of language identification, and number of languages taken into account by the regex should all be considered when determining the winner. But I have not decided on that yet, and am very open to suggestions. In fact this is my first sandbox post and I hope someone can help me format this properly with good rules so that it makes for an interesting and fun challenge. I got this idea from some other contest somewhere where the goal was to identify languages with at least 60% accuracy. But I can't find it anymore. • So only regex submissions are allowed? – user202729 Jul 22 at 6:02 • Although there are options to "weight" the 3 scores differently, the easiest way is to require the other two scores to be larger than some limit (say, at least 2 languages and at least 60%) then compete for the shortest regex. – user202729 Jul 22 at 6:04 • Also, are there any similar challenge before? – user202729 Jul 22 at 6:05 • Yes, only regex is allowed. A very similar challenge I've found is this: codegolf.stackexchange.com/questions/49596/… – GirkovArpa Jul 22 at 6:26 • Also this one, which is linked in the other: codegolf.stackexchange.com/questions/42206/… – GirkovArpa Jul 22 at 6:27 • Pretty similar. But the huge size of the word list will make the solutions different. – user202729 Jul 22 at 6:33 • you should specify a particular flavor of regex. – user202729 Jul 22 at 6:34 • I would have said JavaScript but I thought there could be a winner for each programming language? – GirkovArpa Jul 22 at 6:35 • If you decide to restrict to 2 languages, you may ask for a regex that matches words from list 1 and not match words from list 2. (it may (do anything|never matches) the words that are not in lists) – user202729 Jul 22 at 6:37 • Good idea, I'll do that. – GirkovArpa Jul 22 at 6:39 Write an ASPIF (clasp's ASP input format) program to find a maximum cap set (https://en.wikipedia.org/wiki/Cap_set) for 4 dimensions. Share the code you used to generate the ASPIF rather than ASPIF itself. This may be an ASP program. Winner is smallest word-count (according to wc) in ASPIF format. For ASP, you can get this by running something like: clingo capset.asp --mode=gringo | grep -v "\(^1 0 1 [0-9]\+ 0 0$$\|$$^4$$" | wc -w


(note the grep is for excluding unary rules and #show directives neither of which are necessary for solving. The output of this is still a valid clasp program)

I have an example for four dimensions (but I have a better one I won't share right away because I'm curious to see what other people get).

feature(number, (one; two; three)).
feature(color, (red; green; purple)).
feature(shape, (oval; diamond; squiggly)).
dimension(D) :- feature(D, _).
card(c(N,F,C,S)) :-
property(c(N,F,C,S),number,N) :- card(c(N,F,C,S)).
property(c(N,F,C,S),color,C) :- card(c(N,F,C,S)).
property(c(N,F,C,S),shape,S) :- card(c(N,F,C,S)).

{in_capset(X) : card(X)}.
:~ in_capset(X).[-1,X]

settable(D, A, B, C) :-
feature(D, A); feature(D, B); feature(D, C); A != B; A != C; B != C.
settable(D, A, A, A) :- feature(D, A).

:- in_capset(X); in_capset(Y); in_capset(Z);
settable(D, A, B, C) :
dimension(D), property(X, D, A), property(Y, D, B), property(Z, D, C);
X < Y; Y < Z.

#show in_capset/1.


This grounds to an ASPIF program with 9296 "words"

• 4D cap set is already known and has a pattern which was found in a challenge of mine, so it might be too trivial. Why not ask to take n as input and solve for n dimensions (without time and memory limit)? – Bubbler Aug 7 at 3:32
• Also, most people here are not familiar with ASP or ASPIF. It would be helpful if you include relevant links, so we can do some research before tackling the challenge. – Bubbler Aug 7 at 3:34

# Introduction

"Do not go gentle into that good night" is the title of a poem by 20th century English poet Dylan Thomas. If you've heard it before it was probably because you watched Interstellar, where it was quoted multiple times.

# Challenge

Your program (or function), if it chooses to not go gently, should take no input and print the following text, with an optional trailing newline:

Do not go gentle into that good night,
Old age should burn and rave at close of day;
Rage, rage against the dying of the light.

Though wise men at their end know dark is right,
Because their words had forked no lightning they
Do not go gentle into that good night.

Good men, the last wave by, crying how bright
Their frail deeds might have danced in a green bay,
Rage, rage against the dying of the light.

Wild men who caught and sang the sun in flight,
And learn, too late, they grieved it on its way,
Do not go gentle into that good night.

Grave men, near death, who see with blinding sight
Blind eyes could blaze like meteors and be gay,
Rage, rage against the dying of the light.

And you, my father, there on the sad height,
Curse, bless, me now with your fierce tears, I pray.
Do not go gentle into that good night.
Rage, rage against the dying of the light.


This is , so smallest code in bytes wins.

# Sanbox

• Is this too bland/simple of a challenge? There's a lot of potential for compressing the poem, but it's not really complex.
• Just be careful it isn't marked as a duplicate of this – Lyxal Aug 15 at 3:09
• Is the string being different not enough? – nope Aug 15 at 12:31
• I hope this one is different enough. Things like this are usually borderline since there are several lyrics question closed but some are still open. – null Aug 15 at 14:51
• Despite some interesting repetition in this poem, I think the text compression methods used would be the same, making it a duplicate. – xnor Aug 16 at 6:52

# Gray codegolf

The gray code is a binary numeral system such that two successive values differ in only one bit.

Decimal Binary  Gray
0       0000    0000
1       0001    0001
2       0010    0011
3       0011    0010
4       0100    0110
5       0101    0111
6       0110    0101
7       0111    0100
8       1000    1100
9       1001    1101
10      1010    1111
11      1011    1110
12      1100    1010
13      1101    1011
14      1110    1001
15      1111    1000


# Challange

Print the first k Gray code numbers, starting from 0. The shortest code wins!

You may choose the output format as long as it's human-readable.

# Similar questions

• Why the strict output format, and why the arbitrary constant limit of 1000 (not taking an input number)? Also, possible dupe. – Bubbler Aug 28 at 4:19
• When you say first 1000, is that decimal or binary? – Jo King Aug 28 at 7:55
• The challenge I linked is code golf. – Bubbler Aug 28 at 16:06
• @Bubbler nvm, it looks like I am banned from posting lol – Ilya Gazman Aug 28 at 17:35
• printing a sequence and finding a number in a sequence tend to be very similar tasks. – Razetime Sep 1 at 3:28

# B-a-NaN-a code-golfkolmogorov-complexityrestricted-source

Somewhat famously, 'B' + 'a' + + 'a' + 'a' returns BaNaNa in Javascript. You goal is to output precisely BaNaNa. However, to keep it more in the style of the original Javascript, you may not use:

• The bytes 78 or 110
• Whatever n or N are encoded as if your language uses a special encoding, or
• Any string literal containing the characters n or N

As a special note, I'd like your feedback as to if restricting numeric literals equal to 78 and 110 would be any good.

Additionally, this is my first question, and I'm aware that 'Do X without Y' is officially not super popular these days, but I frankly quite enjoy them, so I have no idea if this will be well-received or not. I'm hoping that the reference to the JS quirk is enough to make it interesting.

• Restricting numeric literals would just result in 77+1 or +"78" or whatever trivial workarounds, so I don't particularly think it's a good idea. For the challenge itself, I don't know if it'll be well-received either. (For the record, BaNaNa = Barium Sodium Sodium = atomic number 56 11 11.) – Bubbler Sep 7 at 3:37
• Since this is such a short string composed only of letters, it's very, very simple to work around it. You need a better restriction method. See this, and the questions in restricted-source – Razetime Sep 7 at 4:24
• Indexing into custom character sets will make this trivial. – Adám Sep 7 at 5:03
• JS, 11 bytes: Ba\${+"a"}a – Redwolf Programs Sep 7 at 14:44

# Find the nth positive integer m for which $$\\tan(m) > m\$$code-golfmath

Write a program/function that when given an integer $$\n\$$ as input outputs the $$\n\$$th positive integer $$\m\$$ for which $$\\tan(m) \gt m\$$.

Note: $$\m\$$ is in radians

## Scoring

This is so shortest bytes wins.

## Sample Testcases

# n -> m
1   -> 1
2   -> 260515
3   -> 37362253
5   -> 534483448
9   -> 214112296674652
10  -> 642336890023956
16  -> 4285797387061825747646013


Find more at A249836

Inspired by What is the biggest tangent of a prime?

• +1 for referencing a MegaFavNumbers video. – Razetime Aug 20 at 3:24
• I don't understand the point. Are you asking us to find the nth number such that tan(x) > x? Is there any approach that will be shorter than iterating over all numbers until you find the nth number such that tan(x) > x? – the default. Aug 20 at 3:33
• Where is n in the equation? I'm lost. – V. Courtois Aug 20 at 9:07
• @Razetime On the channel Stand-up Maths, right? – Rosie F Aug 20 at 18:49
• replace "nth" with "first" "second" etc -> "first/second/etc number m for which ..." i.e. n is not in the equation @V.Courtois – golf69 Aug 20 at 20:30
• @Mukundan314 maybe indicate that n is the input? – golf69 Aug 20 at 20:31
• @golf69 oh! So it has to be an integer, not a number. I see now :) And yes, indicating n is the input would be nice. – V. Courtois Aug 21 at 6:50
• I don't really see this being solved any way that taking the generic golfiest code for "find the n'th number meeting [predicate]", of which there's plenty of challenges, and sticking in tan(m)>m for the predicate. – xnor Aug 22 at 7:04
• Solutions relying on floating-point arithmetic will get the wrong answer starting around the 11th term. You’ll need to clarify whether that’s acceptable. – Anders Kaseorg Aug 22 at 22:14

# Create a Drawing Guide for a Polygram

Poor old Jim, he's just terrible at drawing polygrams, and he's asked you to create a "drawing guide" for him - an ascii polygram with numbered edges, so he can follow the instructions.

## Challenge

Write a program to produce an ascii polygram with P <= 10; each edge of the polygram should be made of a single digit 0-9, showing the order in which the edges should be drawn.

## Input

Your program should receive (via STDIN, as function arguments, or some other language-appropriate method): P, the number of edges/vertices of the polygram, and Q, the spacing. In the notation as per the Wikipedia link, you'll be drawing a {p/q} polygram.

## Output

Either print to STDOUT or return (or something else language-appropriate) a multiline string showing the drawing guide for the given polygram. The string can be any size you like, as long as it's large enough to display a clear polygram.

## Notes

Your code should be able to handle compound regular polygons as well as regular regular polygons, and also inputs of q > p/2 (poor old Jim doesn't realize that the polygram for {p/q} is the same as for {p/p-q}).

## Example Output for {10,3}

              5
5 4
4
21     5        888
2 11115     8888  7
2    5111888 4    7
2     888111  4   7
2  888      111   7
8885           4117
8882               4 711
8   2 5               7  111
25               47
9   5                 7    0
9  2                 74  0
52                 7  0
9 2                 7 4
5 92                 7 04
9                 70  4
5   2                 7
5    29                7    4
6666 2 9              07   33
666              0 7333
2 696           337
2   9666     333  7
2    9  66633 0   7
2      333 666    7
2   339       666 7
2333   9    0    67
9  0
0


## Scoring

This is code-golf, so shortest in bytes wins. Tiebreaker goes to the most votes.

• I have a python solution to this which is ~600 bytes, so it's definitely doable, and it's not easy... – sirpercival Apr 27 '15 at 4:31
• I think the spec needs to be more prescriptive for this to make a good question, especially since the example seems to indicate that you're not currently even prohibiting the lines from having gaps. At a minimum I would say that you should require the lines to be equivalent to those produced by Bresenham's algorithm, and specify how overlaps should be handled; at the extreme, you could tie it down so tightly that it becomes a parameterised kolmogorov-complexity. – Peter Taylor Apr 27 '15 at 9:34

# Pointer to pointers to pointers to pointers

You should choose a language supporting pointers like C. And your task is simple: demonstrate a legitimate use of the most level of pointers.

You should justify your code by describing an algorithm that:

• Has only plain text, number or an array of those as input and output.
• You think it will make things easier to write those code as a part of the implementation of this algorithm.
• This implementation would have optimum memory usage (only declared variables and parameters, explicitly allocated space, and the return addresses for recursive functions count).

Other rules:

• They must be pointers to pointers directly, i.e. a pointer to an object containing a pointer doesn't count. It's better if nobody using this code will want to extend some pointer to an object later.
• Each pointer must have a different type (if your language can somehow make them the same type).
• You should create at least one pointer, and either dereference or compare two non-null pointers once in each level.
• Using pointers as arrays is only half as interesting.
• Iterators, etc, are considered in essence pointers and allowed in this challenge. But you can't define new types implementing iterators for this purpose.

• Could you specify "legitimate"? This sounds a bit like code bowling (and seems to have the same issues). With enough imagination I'm sure I can justify any depth of pointers. – Martin Ender Apr 30 '15 at 17:43
• @MartinBüttner Edited but, basically, it is subjective. – jimmy23013 Apr 30 '15 at 17:57
• @MartinBüttner Added a restriction to have optimum memory usage. I'm not sure whether it works. – jimmy23013 Apr 30 '15 at 18:19

# Winning Tic-Tac-Toe lines

For a given tic-tac-toe board of size N**D (for example, a normal tic-tac-toe game is 3**2), the number of winning lines of length N is given by the expression:

$$2^{D-1} + \sum_{S=1}^{D-1}2^{S-1}DN^{D-S}$$

(Basically, you are summing the number of lines in each S-dimensional slice of the board.)

# The challenge:

Given N and D, your answer should output a list of D-dimensional coordinates for each winning line. Input and output are any reasonable format. You can assume that both N and D are positive integers, with N > 1. (Degenerate cases of N=1, D>1 not included.)

• How do you intend to determine which of two answers is fastest? – Peter Taylor May 12 '15 at 19:37
• yes, @randomra made the same point on chat. i'll edit this in, but i guess... i'll put together some test cases and then time them? i dunno, i was going back and forth between this and code-golf, but i'd prefer interesting and readable algorithms. – sirpercival May 12 '15 at 20:10
• i posted this here because i really want the answer, and i hate coming up with brute force solutions... :D – sirpercival May 12 '15 at 20:16
• Um. Given that you're asking people to enumerate an exponentially large set, in what sense will the answers not be brute force? – Peter Taylor May 12 '15 at 20:28
• well, there's brute force and then there's brute force. but really it's because i don't want to do it myself, haha. – sirpercival May 12 '15 at 20:34
• also, making use of symmetry can severely reduce the computation. – sirpercival May 12 '15 at 20:40
• I imagine that the runtime in any such algorithm will be basically proportional to the number of things you print, so there won't be any good way to improve by algorithm and the speed will be very platform-dependent. – xnor May 12 '15 at 23:40

# Ayn Random number generator

Inspired by xkcd 1277:

Write a random number generator that takes no input and generates a random integer between 1 and 100. When run less than 200 times, the frequency of all numbers needs to be between 0 and 2, but when it's ran 50 000 times, the number 42 (obviously) should have a frequence that's more than 4 standard deviations higher than the mean.

• 1. I think it's difficult to decide objectively whether a PRNG appears to be fair at first sight. 2. The term more often should probably be quantified. – Dennis May 18 '15 at 21:49
• I see lots of C rand()%1000 and the like incoming... – rorlork May 18 '15 at 22:05
• @Ypnypn I have changed the criteria to have much lower numbers so they're easier to verify. – Nzall Jun 6 '15 at 13:04
• @Dennis I have rewritten the question to clarify what "being fair" is and what "more often" actually entails. – Nzall Jun 6 '15 at 13:05
• 1. Are you thinking of a standalone program that you run multiple times or a function that is allowed to keep a state? In the first case, not even a perfect RNG will, with overwhelming probability, satisfy the first condition. 2. Do you mean the mean and standard deviation of a perfect, uniform RNG or the one the code implements? – Dennis Jun 6 '15 at 23:44
• @Dennis I'm thinking of just a function AynRandom() that gets called. The frequency of numbers with a small number of iterations is subject to change, maybe from 0 to 4. The mean and Standard Deviation must be the one the code implements. – Nzall Jun 7 '15 at 9:49
• between 0 and 2 ? so print 42 would be a valid program ? – Falco Jun 11 '15 at 15:32
• @Falco No, because 42 would appear more than 2 times (unless you only run it twice). The problem is that I need a way to indicate that the RNG is fair with a low iteration count, but unfair with higher iteration counts. The only way I can make it work is by stating that with low iteration counts, all numbers should appear about equally often, which is either 0, 1 or 2 times. – Nzall Jun 11 '15 at 15:36

Please nitpick this. If there's anything that wouldn't work or would be inconvenient, however small of an issue it is, tell me about it!
Also, suggestions for [adjective] are more than welcome.

# Determine how [adjective] a number is (code-golf)

A number would be considered [adjective] if 0 is the result of multiplying its digits together, then multiplying the digits of the resulting number, then repeating until a single-digit number is produced. The more steps it takes to reach 0, the more [adjective] the number is; if the resulting number is not 0, though, the number is not [adjective] regardless of how long it took to finish.
The formula used to determine [adjective]-ness is 10-10/T where T is however many numbers it took to reach 0 (including 0 and the initial input)

Your goal is, as the title says, to write a program or function that determines how [adjective] a number is, and prints every iteration along the way. Here are some example inputs/ouputs:

in: 879
out: 879    <-       (T=1)
504    <- 8*7*9 (T=2)
0      <- 5*0*4 (T=3)
<- optional newline
6.6... <- 10-10/3 (repeating decimals can be expressed in any way you want)

in: 2468
out: 2468   <-  T=1
96     <- (T=2) 2*4*6*8
54     <- (T=3) 9*6
20     <- (T=4) 5*4
0      <- (T=5) 2*0

8      <- 10-10/5

in: -888
out: -888
-512   <- -8*-8*-8
-10    <- -5*-1*-2
0      <- -1*0

6.6... <- 10-10/3

in: 1344
out: 1344
48
32
6

0    <- did not produce 0, so the prog/func returns 0


-Takes input from STDIN.
-Throws an "error" (printed to STDOUT) and halts immediately after input if the input has one or more 0s in it or if it's less than three digits in length. The error must be a string, and as it's supposed to be printed to stdout, cannot be one generated by the language itself (eg 1/int(min(input())) to check if it's zero). Lastly, the error message has to clearly define what the error is; ERR:0 and ERR:LEN, for example, would suffice.

Bonuses/Penalties:

-25 if it properly handles decimals. For instance, an input of 99.22 would first turn into 9*9 + 0.(2*2), or 9*9 + 0.4, and so on.

This is , so the shortest answer in bytes wins.

• I don't like the +15 penalty. Whether strings are used is vague in some languages. The constant amount +15 is too little deterrent for some languages but huge for very concise ones. The fact that you've found a short solution you don't like is sign you should rethink the problem, not try to plug the hole. – xnor Jun 17 '15 at 7:48
• @xnor that's reasonable. I suppose it is a valid way of doing it, anyway, so I removed all mention of strings in that section. Should I also inc/decrease the bonus for decimals? – hallo Jun 17 '15 at 22:29
• The programming languages I know either don't allow throwing user-defined errors or print them to STDERR. Now, if you just want us to print a message and exit immediately... – Dennis Jun 17 '15 at 23:32
• ...and should be printed to STDOUT. I had a feeling that wasn't clear; I edited it, is it better now? – hallo Jun 17 '15 at 23:33
• It's the word throw that throws me off (no pun intended). To throw an error usually means something rather specific. Print an error message to STDOUT (or closest alternative) would be less confusing in my opinion. Also, since this is code golf, I think you should require specific error messages. There's no fun in losing a contest because you chose ERR:LEN and somebody else got away with EL. – Dennis Jun 18 '15 at 3:16
• Remove bonuses altogether. It's in the list of things to avoid. – mbomb007 Mar 1 '16 at 21:31
• The error if the input contains a zero seems like a separate challenge. It may be better received if there is only one challenge. There is community support for avoiding Chameleon challenges. – trichoplax Aug 10 '16 at 11:40

# Represent a Number in the Strangest Way You Can Think Of.. while staying under 8 unique characters

Your goal is to represent some numbers in the strangest way possible.

### Rules:

• The result must be a number that can be used in the programming language like any other ordinary number. For instance, <my expression> + 3 should return 3 more than the value of <my expression>.
• The code must be under 20 kilobytes. That's a rather large size for a number so you should be all set.
• The expression must have under 8 unique characters! The length of it can be as long you want, just keep it under 8 unique characters. aaaaaaaaaaaaaaaaaa is valid (if it works in the programming language) but abcdefghijklm isn't valid because it uses 8 or more unique characters.

### Guidelines:

• The goal here is to represent a number in the strangest and most interesting way possible, so if I ask you to represent the number 35 it would be a good idea to respond with something more interesting than 35 or 12 + 23.
• This isn't a ! Feel free to make your code as long as you want, so long as it's under 20 kilobytes. Fancy code can look nice!
• The code doesn't need to support decimals (floats) but if it does, it will get 10 extra points (see below).
• The code also doesn't need to support negative numbers (for instance -37) but if it does, it will get 10 extra points (see below).

# Language

Description

### 0

...


### 1

...


### 30

...


### 108

...


### 1337

...


### 1234567890

...


### 3.1415 [10 bonus points if you can get this!]

...


### -25 [10 bonus points if you can get this!]

...


## Bonus numbers:

...

The points is equivalent to the number of votes on the answer plus 10 if it supports decimals with 10 more points if it supports negative numbers. Whoever has the highest points is considered the current winner. Have fun!

This is my first go at making a popularity contest so if you have any tips those would be appreciated.. :)

• This is a great challenge... whoever downvoted this has to rethink their concept of code-restriction challenges... – WallyWest Jul 15 '15 at 22:49
• Ah, thank you. :) – Florrie Jul 15 '15 at 23:28
• Updated again with negative numbers added (-25), as well as 1 and 0. – Florrie Jul 15 '15 at 23:33
• @Sp3000 8 unique chars, not 8 total. – isaacg Jul 16 '15 at 10:04
• @isaacg Didn't I state that? – Florrie Jul 16 '15 at 11:11
• @liam_ You did, the person I was responding to who deleted their comment missed it. – isaacg Jul 16 '15 at 11:32
• TBH, I think this is such a poor popcon that it can't be rescued, but if you want to at least make it clear what you're asking then: 1. You talk about representing "a" number, but also about "support[ing] decimals" and "support[ing] negative numbers". What exactly do you want? A function which maps numbers to code? But if so, the "Post format" makes no sense. 2. What is the code which has a 20kB limitation? Total for all the numbers listed in the "Post format"? Each individual number listed in the "Post format"? Something else? 3. Are the 8 distinct characters per number or for all numbers? – Peter Taylor Jul 17 '15 at 16:19

# Wrong tool for the task

Write two full programs in the same programming language that solve the following two tasks:

1. Read two positive integers from STDIN and print their sum to STDOUT.

2. Read two positive integers from STDIN and print their product to STDOUT.

• Given enough time and memory, your programs has to support arbitrarily large integers.

• All integers (input and output) use standard decimal notation, have no leading zeroes and are followed by a single linefeed.

### Scoring

The first task is code golf, so your objective is to make your program as short as possible.

The second task is code bowling, so your objective is to make your program as long as possible.

Your score is defined as follows:

The highest score wins!

### Robbing a language

There's a catch! Only the submission with the shortest program in a particular language will be considered valid for task 2, so there can only be one valid answer per language.

This means that you cannot deliberately write a huge program for task 2; you actually have to pick the "wrong tool" for the task.

• Task 1 exists merely to provide the proper denominator for the score (and robbers have no moral anyway), so byte-per-byte copies of somebody's program for task 1 are allowed.

• If two answers use the same language and have programs of the same length for task 2, the answer that achieved that length first will be considered valid.

• @Dennis Wow, you anticipated everything and I missed it. I take it then that input must be as a string of numerical characters? Also, do I understand right that you have to print a newline for output (say, print a+b,"\n"` in Python)?. – xnor Jul 20 '15 at 20:45