Sandbox for Proposed Challenges

Question

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

Sandbox FAQ

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Discussion

The purpose of the sandbox is to give and receive feedback on posts. If you want to, feel free to give feedback to any posts you see here. Important things to comment about can include:

• Parts of the challenge you found unclear
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You don't need any qualifications to review sandbox posts. The target audience of most of these challenges is code golfers like you, so anything you find unclear will probably be unclear to others.

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Other

Search the sandbox / Browse your pending proposals

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Answer 1

Enforce Social Distancing! code-challenge test-battery

Related to Maintain Social Distancing!.

As in that challenge, there is a 2-dimensional array of 1s and 0s representing people. In it, social distancing is maintained if and only if all 1s are at least 6 squares apart, where distance metric used is \$|\Delta x| + |\Delta y|\$ (rectilinear or Manhattan).

The challenge here is to move some people in a given 2D array so that social distancing is maintained. It's guaranteed that it's possible to do so. Your program's score on a given input is the total distance moved by all people.

Your program's running time must not exceed 10 seconds on any of the test cases.

This is tagged test-battery, so there is a large set of inputs your programs will be tested on [TODO: actually create it]. The program with the lowest total score on all of these inputs wins.

Sandbox stuff

• Is this currently a bad idea for the reasons specified by Shaggy in the following comment?

  I am sorry but I have downvoted this for what others may perceive to be a trivial reason: Code Golf is one of the few things I have left where I can escape how fucked my world has become; I absolutely do not want to come here to be reminded that I can't hug my family and friends.

• Is there an optimal algorithm? (I hope not)

Answer 2

Shorten the numbers

These numbers are taking up far too many bytes on my computer. Create a function/program to shorten any number using only Alphanumeric characters as the output.

Scoring

Scoring is based on optimized-output. Shortest number of characters produced for the following randomly generated numbers (plus one special number with repetition) wins. Add the number of output characters output for the 5 test numbers together for total score.

• 94949267912781
• 75477115147709
• 79547324913976
• 12345678998765
• 11111122222222

The score of the non-optimized numbers = 70. (14 * 5)

Sandbox questions

• does scoring make sense?
• should I include a sample script, output, or both?
• should I be more clear the answers should work on any number? (ie. "replacing each test number with one character is disallowed")?

Answer 3

Posted.

Answer 4

Match the entire lyrics of All-Star

The challenge is simple: create a program/function that, when given a string consisting of the entire lyrics to All-Star as they appear in this paste (or not), output whether or not they are, in fact, the entire lyrics. The given string may be off by one of two characters, or something completely different, like Moby Dick (approximately). Output may consist of any of two values that map to true and false. They could be 0 and 1, or t and f, or whatever you like so long as there are two distinct values. You can choose to print the output or return it (if you are a program or a function). This is code-golf, so shortest answer in bytes wins!

Answer 5

Golf me a ^Bookmarklet Quine

Given a javascript program (or any utf-8 text) of arbitrary length, output it in my simplified version of URI form, like a bookmarklet. You can use https://mrcoles.com/bookmarklet/ as reference. Output should be in the form

javascript:[input with percent-encoding for special characters]

Special characters are any character that is not

• Alphabetic (upper or lower)
• a digit
• the characters .,-,_, or ~ (period, hyphen, underscore, tilde)

Your program "should convert all other characters to bytes according to UTF-8, and then percent-encode those values"^w

A percent-encoding mechanism is used to represent a data octet in a component when that octet's corresponding character is outside the allowed set or is being used as a delimiter of, or within, the component. A percent-encoded octet is encoded as a character triplet, consisting of the percent character "%" followed by the two hexadecimal digits representing that octet's numeric value. For example, "%20" is the percent-encoding for the binary octet "00100000" (ABNF: %x20), which in US-ASCII corresponds to the space character (SP). source

Lowercase hex is okay, but uppercase is preferred.

This is code golf, standard loopholes are prohibited, programs should handle input up to 20 lines and output in a single line.

The Twist (so it's not a duplicate)

If run with no input or just a newline (your choice), the program should output itself in the same format as if the program's source was inputted normally.

Examples

In                                              Out

[blank]                                         javascript:[the%20program%27s%20source]
g/re/p                                          javascript:g%2Fre%2Fp
https://www.youtube.com/watch?v=dQw4w9WgXcQ     javascript:https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DdQw4w9WgXcQ
alert("test!")                                  javascript:%7Balert(%22test!%22)

code-golf quine

---

sandbox questions

• What should I add?
• What tags does this need?
• Are my examples inconsistent?
• What parts of the challenge are redundant?

Answer 6

Comment: might be too similar to previous mutual quine challenge?

Collaboration/quasi-quine challenge

Write a valid submission (A) which prints the code for another competitor's valid submission (B). The languages used in A and B must be different.

Clarifying rules

If B prints the code for a third submission, C, it is not required that A and C be different languages. Similarly, the authors of A and B must be different, but A and C need not be. (More different languages/authors score higher, however.)

The shortest chain is for A to print B and B to print A.

Note that if A prints B, and B prints C, but C is not valid for some reason, then neither A nor B are valid either.

It is acknowledged that the validity of your submission may change over time, due to factors beyond your control. Try not to let this worry you too much. :)

Input

None

Output

Just the code described above. Nothing extraneous.

Scoring

Scoring is (A + L) * 100 + C where:

• A is the number of distinct authors that directly or indirect print your solution. So if you are Q, and Z=>X=>Q=>X, your "A" is 2. (Each submission only has one author, the "answerer".)
• L is the number of distinct languages in your quine circle, along the same lines as for authors. (Each submission only has one language. "Distinct" means really different, not just different versions or implementations of the same languages.)
• C is the length of your solution in bytes.

(So, for a given circle of quines, all the submissions will have similar scores, with the length of the submission as tie-break.)

Standard loopholes are forbidden.

Answer 7

Price this word code-golfnumberstring

So, I'm going shopping in the Word Market™. There are shelves of words which I can buy around me, but I only have one dollar bills and the change machines at the market are broken. To add to the problem, there are words with... non-word characters in them. That's no good, I can't buy those... can you help me figure out which words I can buy and which I can't?

Task

So, I can only buy words that consist of only alphabetical characters and are worth a dollar. To determine a word's value, you have to sum the letters in the word where A = 1¢, B = 2¢... to Z = 26¢. I'm too lazy to look at the output and judge whether it is equal to one dollar (100 cents), so you'll need to return a specific value for words equal to a dollar (...or 100 cents) and a specific value for not equal to a dollar (I'm going to stop including this).

I'll also offer a bonus byte reduction: if your code returns whether the word is less than a dollar, equal to a dollar, greater than a dollar, or invalid (e.g. <, =, >, x), your score will be multiplied by 3/4.

SANDBOX NOTE: Is this a balanced bonus value?

Examples

Word          Non-bonus value     Bonus value

a                  false               <
b                  false               <
printera           false               >
$word              false               x
printer            true                =

And here's a JavaScript snippet you can use if you want to check for non-bonus validity:

(it's also 52 bytes; you can use it by calling f())

f=s=>([...s].map(x=>a+=parseInt(x,36)-9),a==100),a=0

Anyways, standard loopholes apply, shortest answer in bytes wins (but I'll add shortest answers for esoteric and functional languages)... you get the idea.

Answer 8

Magic card trick: Hide information by flipping cards

_{(This is inspired by a series of questions on puzzles.stackexchange.com: 10, 8, 7)}

Fix two integers m and u. Your task is to perform the following magic trick:

• A Magician brings a pack of m distinct cards, and leaves the room.

• In their absence, a volunteer from the audience shuffles the deck and arranges all cards in a line, in any order they want.

• Still in the absence of the magician, their assistant flips u cards. On the table are the n cards, still in the order chosen by the volunteers, but u are face down, leaving only m−u cards face up.

• The magician returns, and from the order of the cards alone, knows each card.

Input:

m - number of cards.

u - number of cards to flip face down.

• You may assume 0 < u < m.

Output, if the trick is possible for m and u:

f - an mapping assigning to each sequence the order the assistant will create by flipping cards.

• If the trick is to work, this mapping must be bijective.
• Use the integers 1...m (or 0...m−1), or single letters as card values.
• Use any meaningful way to express f: a hash maps, a table, a function.
• Use a fixed placeholder for any face-down cards.

Output, if the trick is impossible for given values of m and u

This case should be indicated in a meaningful way.

Example output (m=3, u=1):

Using the digits 0, 1, and 2 as cards, and _ for their flipside:

012 01_
021 0_1
102 _02
120 12_
201 2_1
210 _10

_{(For these values of m and u, this isn't very impressive as a magic trick, of course.)}

Example output (m=4, u=2):

Using 1, 2, 3, and 4 for the cards and 0 for their flipside, and a JSON representation:

{"1234":"0034","1243":"0043","1324":"0024","1342":"0042","1423":"0023","1432":"0032",
"2134":"0104","2143":"0103","2314":"0014","2341":"0041","2413":"0013","2431":"0031",
"3124":"0120","3142":"0102","3214":"0204","3241":"0201","3412":"0012","3421":"0021",
"4123":"4003","4132":"0130","4213":"0203","4231":"0230","4312":"0302","4321":"0301"}

_{This is correct because as required, the keys are all permutations of 1234, each value has two cards face-down and the other cards match the original sequence, and each value appears only once.}

Scoring

This is code-golf. Shortest solution wins.

Answer 9

_

Answer 10

Mobile games money representation

In many mobile clicker games where the player is usually required to tap on the screen to make money (in order to buy upgrades for you to generate money faster), it gets to a point in the game that the money made per second is so big that if represented in its "normal" form, it would clutter the mobile screen. Imagine showing the user that they are making \$1,000,000,000,000,000,000,000,000\$ per second in a small mobile phone screen!

From my experience as a regular player of these type of games, I have noticed that most of them represent bigger numbers by using letters. If the number of money per second is a number less than \$10,000,000\$ then print the number as is. Otherwise, if the number is in the millions (but \$ \geq 10,000,000\$), for example \$ 102,000,000\$ it should print \$102M\$. If it is in the billions, it should print \$102B\$. You should use \$T\$ for trillion and \$Q\$ for quadrillion.

As you can notice, the next would be quintillion which would also use the letter \$Q\$ if followed the pattern. Instead of following this pattern which can be confusing at one point, game developers usually start a new pattern: Quintillion is used with the suffix \$AA\$, sextillion is \$AB\$, septillion is \$AC\$ and so on.

Notice that this pattern would go until \$AZ\$ and if the player is making more money than that, it would start from \$BA\$, \$BB\$, ..., \$BZ\$, ...,\$ZA\$, \$ZB\$, ... , \$ZZ\$ which for our problem we will assume is the limit one player can make per second.

Task

Given an integer \$x\$ where \$0 \lt x \leq 999\$ and a natural number \$y\$ where \$y \gt 0\$ representing the number of zeroes the number has, output the number in a "mobile game money representation" as described above.

Observations

• The number of zeroes that \$y\$ represent does not include the possible zeroes \$x\$ might have! Example: if \$x = 100\$ and \$y = 6\$, you should output \$100M\$ and not \$1,000,000\$

Test Cases (x, y --> game money representation)

100,  6 --> 100M
100,  5 --> 10M 
100,  4 --> 1000000
1,   12 --> 1T
10,  12 --> 10T
100, 12 --> 100T
1,   18 --> 1AA
10,  18 --> 10AA
100, 18 --> 100AA
# To be added...

Meta questions

1. Is this a duplicate? I have looked around but didn't find anything similar.
2. Is the wording confusing? I'm open to recommendations!
3. I haven't written a program yet so the test cases might be wrong (I'll add more later).
4. Pretty much any feedback is appreciated!

Answer 11

Shift the letters, soldier !

posted, finally

Answer 12

Compute the pointiness, sharpness and smoothness of a letter code-golf kolmogorov-complexity

^{Inspired by Determine the sharpness of a word.}
You are given an uppercase letter of the English alphabet as input. You have to compute (and output) its pointiness, sharpness and smoothness. Since it is difficult to define these objectively, here's a table of the outputs:

            A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
pointiness: 2 0 2 0 3 3 2 4 4 2 4 2 2 2 0 1 1 2 2 3 2 2 2 4 3 2
sharpness:  1 2 0 2 2 1 1 0 0 1 0 1 3 2 0 1 0 1 0 0 0 1 3 0 0 2
smoothness: 0 2 1 1 0 0 1 0 0 1 0 0 0 0 1 1 1 1 2 0 1 0 0 0 0 0

Transposed version (first lists the letter, then the pointiness, then the sharpness and then the smoothness) ^{(like a true CGCC user, I transposed it with Jelly and added spacing with Retina)}:

A 2 1 0
B 0 2 2
C 2 0 1
D 0 2 1
E 3 2 0
F 3 1 0
G 2 1 1
H 4 0 0
I 4 0 0
J 2 1 1
K 4 0 0
L 2 1 0
M 2 3 0
N 2 2 0
O 0 0 1
P 1 1 1
Q 1 0 1
R 2 1 1
S 2 0 2
T 3 0 0
U 2 0 1
V 2 1 0
W 2 3 0
X 4 0 0
Y 3 0 0
Z 2 2 0

Bonus imaginary internet points if you find a language where this is built-in.

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

Sandbox stuff

• Is this not a duplicate?
• Is the table computed correctly? (the only ones that don't seem certain with the current font are I's pointiness, G's sharpness and S's smoothness)

Answer 13

Is this a simple cutting template?

A simple cutting template is a rectangle that can be recursively cut into smaller rectangles using only full-width cuts.

If you prefer a bottom-up description, then:

• A single rectangle is a simple cutting template with 0 cuts.
• Two simple cutting templates of the same width (or length) can be joined along their common side into a larger simple cutting template.

Input: A diagram of a rectangle subdivided into smaller rectangles, or a list of rectangles in some standard format, e.g. position and size.

Output: A truthy value if the diagram is a simple cutting template.

Note that if you take input as a diagram then all of the rectangle edges will use the same character, whearas in the truthy examples below, some of the edges have been replaced with digits to show a possible ordering of cuts while the falsy examples have the smallest portion of the input that is not a simple cutting template marked on them.

####2################
#   2               #
111111111111111111111
#                   #
#                   #
#                   #
111111111111111111111
#     2   2   2 4 4 #
3333332   2   2 4 4 #
# 4   2   2   2 4 4 #
# 45552   2   2 454 #
# 4 6 2   2   2 4 4 #
# 4 6 2   2   2 4 4 #
# 4 6 2   2   2 4 4 #
33333323332   2 4 4 #
#     2   2   2 4 4 #
#     23332   2 4 4 #
#     2   2   2 4 4 #
#     2   2   233333#
#     2   2   2     #
######2###2###2######

-> Truthy

##2#####4############
# 2     4           #
# 2333333333333333333
# 2         6     4 #
# 25555555555555554 #
# 2 6   6     8   4 #
# 2 6   67777777774 #
# 2 6   6         4 #
# 2 6   6         4 #
# 2 6   6         4 #
111111111111111111111
#               2   #
#               2333#
#               2   #
111111111111111111111
#   2             2 #
#   233333333333332 #
#   2 4 4     4   2 #
#   2 4 4555554   2 #
#   2 4 4     4   2 #
####2#############2##

-> Truthy

#####################
#                   #
#                   #
#                   #
111111111111111111111
# 2   4           2 #
# 2   4           2 #
# 2   4           2 #
# 23333333333333332 #
# 2     4   4 6 4 2 #
# 2     45554 6 4 2 #
# 2     4 6 4 6 4 2 #
# 2     4 6 4 6 4 2 #
# 2     4 6 4 6 4 2 #
# 2     4 6 45554 2 #
# 2     4 6 4   4 2 #
# 2     4 6 4   4 2 #
# 2     4 6 4   4 2 #
# 2     4 6 4   4 2 #
# 2     4 6 4   4 2 #
##2#####4#6#4###4#2##

-> Truthy

#####################
#               # # #
################# # #
#               # # #
#               # # #
#               # # #
?????????############
?     # ?     #     #
?     # ?     #     #
?     # ?     #     #
?     ##?     #     #
?     # ?     #     #
?###### ?############
?     # ? #       # #
?     # ? #       # #
?     # ? #       # #
?###### ?##       ###
? #   # ? #       # #
? ######? #       # #
? #     ? #       # #
?????????############

-> Falsy

?????????????????????
?     # # # # #     ?
?###### # # # #     ?
?     # # # # #     ?
?     # # # # ######?
?     # # # # #     ?
?###### # ##########?
? #   # # #         ?
? ##### # #         ?
? # # # # #         ?
? # # # # #         ?
? # # # # #         ?
? ####### #         ?
? #     # #         ?
? #     ############?
? #     #     #     ?
? #############     ?
? #     #     #     ?
? ##################?
? #         #       ?
?????????????????????

-> Falsy

#####################
#       #   #     # #
################### #
#                 # #
#####################
# #                 #
# ###################
# #   #             #
# ###################
# #   #     #       #
# ###################
# #                 #
# ???????????????????
# ?   #             ?
# ?   #             ?
# ?   #             ?
# ?   ##############?
# ?   #   #         ?
# ?########         ?
# ?       #         ?
##???????????????????

-> Falsy

This is code-golf, so the shortest program or function that breaks no standard loopholes wins.

Answer 14

ax + by, a & b are coprime code-golf integer number-theory

Backstory

A doctor in Berlin, after analyzing his medical history, has realized that all of the results of his integral measurement results can be represented in the form of \$23x+28y\$, where \$x\$ and \$y\$ are integers.

However, he could have extended his theory. \$23\$ and \$28\$ can be replaced by any two coprime numbers, and this theory would still hold. (He didn't have time to write his theory in a paper, that's quite awful.)

Task

Without examples, I'll never be convinced that this nonsensical theory holds!

Given \$the\ output\ of\ (ax+by)\$ (let's call it \$z\$), \$x\$, and \$y\$, find the smallest pair of \$(a,\ b)\$ that makes \$ax + by = z\$ true.

Example cases

Answer 15

Duplicate of Find the minimum edit distance between two strings

Answer 16

Partition distance code-golf string

Quoting Anush:

I am very glad to provide a service to fill in the terrible gap in edit distance questions which codegolf.se has had. When there are as many edit distance questions as quine questions my job will be done.

--Anush

Task

Given a binary string consisting only of 0's and 1's, partition the binary string (divide the string into consecutive substrings), and determine the minimal edit distance in order to transform one piece into another, left to right. You need to output the sum of the edit distances between consecutive blocks.

Example

I'm going to make a reference implementation to find the optimal partitions. But that's after I dump all my ideas, though.

011010110111

We partition the string like this:
[011][010][110][111]

And then find the cumultative edit distance between each 2 pairs of partitioned strings:
[1 1 1]

Then, we sum the list of partitions.
[3]

So 3 is a possible output for this binary string. However, you need to find the minimum edit distance, so this might not be the correct answer.

Another example

001001010

We partition this string:
[001][001][010]

And then find the mimimal edit distance between each piece.
[0 1]

Therefore, our (non-optimal?) output for 001001010 is 1 ([0 1] summed).

Rules

• The edit distance between two strings is the minimum number of single character insertions, deletions and substitutions needed to transform one string into the other.
• The input is guaranteed to have at least length 3.
• The pieces of your partition don't have to be the same length.

Answer 17

Compute the factorial, on both sides of 0

Why, why, why do factorials stop at zero? (Yes there are actual reasons). Make a factorial function (or full program) that doesn't stop at zero!

Your code-golfed program should, given an non-zero integer n (can be positive or negative, the rule still applies), find the product of the range n to -n excluding 0.

Graph that at least works for positive numbers

Sample IO

 Input          | Output
----------------|------------
0               | 1 (product of 0 and -0 without 0 / empty product)
2               | 4 (2*1*-1*-2)
3               | -36 (3*2*1*-1*-2*-3)
4               | 576 (4*3*2*1*-1*-2*-3*-4)
-4              | 576

Probably not a duplicate, but it might not be that much of a challenge.

code-golf factorial

Answer 18

Default Lightning Strike

code-golfascii-artrandomstring

Introduction:

Inspired by this reddit question: ELI5: Why does lightning travel in a zig-zag manner rather than a straight line?

Although it's more complex than this, in general multiple lightning paths will randomly check its immediate surrounding for the direction with least resistance (based on air pressure, temperature, composure, humility, etc.) and travel in that direction. As soon as one of the paths reaches the ground, that entire path has the least resistance and most (although not all) of the ions will accumulate in that path, causing the lightning flash and thunder.
Here a slow-mo video of a lightning strike to get an idea.

Challenge:

Input: An integer \$h\geq3\$ and an integer \$1\leq p\leq\left\lfloor\frac{h}{2}\right\rfloor\$

Output: Each step of the ASCII animation of a random lightning strike, with a cloud to earth height of \$h\$ and up to \$p\$ paths

We start with a lightning ion at the cloud, with a lowercase letter of your own choosing (i.e. b). This ion will travel in a random direction (horizontally, vertically, or (anti-)diagonally), except where this path itself comes from. Every 'tick' it also has a 20% chance of branching out into two paths, as long as we haven't reached \$p\$ paths yet. Each of these paths will behave the same.
As soon as any path hits the ground based on the height \$h\$, all letters of that particular path will become uppercase, and in the final 'tick' after that, only this uppercase path will remain.

Challenge rules:

• Paths can intersect with other paths
• Paths can travel upwards beyond the height of our starting point
• Output can be in any reasonable format. Could be a list of multi-line strings for each 'tick'. Could be a list of character-matrices for each 'tick'. Could be pretty-printed to STDOUT (with clear non-whitespace separation between each 'tick' - i.e. a single character like a comma or semi-colon, or a line of --- or ___)
• Trailing spaces for each line of a tick are optional (leading as well, as long as the lightning bolts are still correct)
• If multiple paths strike the ground in the same 'tick', only the first one of those two (or more) paths will become the lightning strike. The order in which paths are created are therefore important, so keep that in mind.

Examples:

This may all sound pretty vague, so here a couple of examples:
(I've added trailing spaces for each step with spaces, but you don't necessarily have to do so as mentioned in the challenge rules.)

Example 1: \$h=3, p=1\$

Tick 1:
"b"
" "
" "
Tick 2 (random direction: right):
"bb"
"  "
"  "
Tick 3 (random direction: up-left):
"b "
"bb"
"  "
"  "
Tick 4 (random direction: down-left):
" b "
"bbb"
"   "
"   "
Tick 5 (random direction: down):
" b "
"bbb"
"b  "
"   "
Tick 6 (random direction: up-right):
Note that this overlaps with a previous step in this path, which is fine.
" b "
"bbb"
"b  "
"   "
Tick 7 (random direction: down-right):
" b "
"bbb"
"b b"
"   "
Tick 8 (random direction: down):
" b "
"bbb"
"b b"
"  b"
Tick 9 (lightning strike):
" B "
"BBB"
"B B"
"  B"
Tick 10 (extra tick to remove all other paths, although there are none right now):
" B "
"BBB"
"B B"
"  B"

Example 2: \$h=5, p=2\$

Tick 1:
"b"
" "
" "
" "
" "
Tick 2 (random direction: down-left):
" b"
"b "
"  "
"  "
"  "
Tick 3 (random direction: down-left):
"  b"
" b "
"b  "
"   "
"   "
Tick 4 (random direction: right):
"  b"
" b "
"bb "
"   "
"   "
Tick 5 (random 20% path split; random direction 1: top-right, random direction 2: right):
"  b"
" bb"
"bbb"
"   "
"   "
Tick 6 (random direction 1: top-left, random direction 2: down):
" bb"
" bb"
"bbb"
"  b"
"   "
Tick 7 (random direction 1: left, random direction 2: down-right):
"bbb "
" bb "
"bbb "
"  b "
"   b"
Tick 8 (lightning strike of path 2):
"bbB "
" Bb "
"BBB "
"  B "
"   B"
Tick 9 (extra tick to remove all the other paths, which is path 1 in this case):
"  B "
" B  "
"BBB "
"  B "
"   B"

General rules:

• This is code-golf, so shortest answer in bytes wins.
  Don't let code-golf languages discourage you from posting answers with non-codegolfing languages. Try to come up with an as short as possible answer for 'any' programming language.
• Standard rules apply for your answer with default I/O rules, so you are allowed to use STDIN/STDOUT, functions/method with the proper parameters and return-type, full programs. Your call.
• Default Loopholes are forbidden.
• If possible, please add a link with a test for your code (i.e. TIO).
• Also, adding an explanation for your answer is highly recommended.

---

Sandbox Questions:

• Should I perhaps use a different letter of the alphabet per path?
  • If yes: what would happen when different letter-paths overlap? I assume the top one will be visible per 'tick', but if lightning is struck it should still change it to the underlying letter as uppercase. In either case, you'll have to keep track of each individual path and uppercase only the one that struck the ground (first).
• Any additional rules or things that are unclear?
• An additional relevant tag?
• More examples with more paths and/or larger height?
• A different path percentage instead of hard-coded \$\frac{1}{5}\$ / 20%.

Answer 19

Sort numbers using as few distinct bytes as possible

Task

Write an algorithm that takes as input an ordered list (array, linked list, etc...) of numbers and outputs an ordered list containing the same numbers sorted by their value (ascending or descending).

The numbers may be represented using the most convenient format to you, with the only restriction that there must be a way to encode 256 distinct numbers. You are not allowed to use built-in sorting functions/algorithms.

Scoring criteria

Let \$c\$ be the number of distinct bytes in your code* and let \$s\$ be the number of bytes in your code*.
*Or its UTF-8 representation

The score is equal to \$c^2 + s\$. The answer with the lowest score wins!

Examples (imagine these are sorting algorithms):

• ababccbaacbabcba → \$c=3, s=16, score=25\$
• aAbcd€f → \$c=9, s=9, score=90\$
• bytes 16 ee 3c 79 ee → \$c=4, s=5, score=21\$

---

I'm open to suggestions, especially about the score formula.

Answer 20

Fix mispellings code-golf kolmogorov-complexity

Wikipedia has a list of common misspellings, and there is also a machine-readable version!

Your challenge is to input a string and fix the mispellings in it.

The parituclar list we'll be using is https://en.wikipedia.org/w/index.php?title=Wikipedia:Lists_of_common_misspellings/For_machines&oldid=962756669#The_Machine-Readable_List. Note that even if the list changes, you must use this version. Here's a pastebin link: https://pastebin.com/j03aL98d.

Each line in the list is in the format INPUT->OUTPUT1, OUTPUT2, OUTPUT3, ... (of course, there may be more or less possible outputs, or even just one). That means that for input INPUT you must output exactly one of the possible outputs OUTPUT....

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

Sandbox stuff

Should I add more misspellings to the post, or should I remove them?

Answer 21

Overlap characters code-golf

Put all the characters of a given list, following the order, in a sequence of bits keeping it as small as possible.

Rules

• Write the bits of each character on a line.

• You can overlap bits if they are equal.

• You cannot change already written bits.

• Extend the line, in both directions, if not all the bits fit in.

• Always try to extend as less as possible.

Example

input :['a','&','1','.']
     0110 0001  // a
0010 0110      // &
           001 1000 1     // 1
                 00 1011 10 // .
                 
output :0010011000011000101110

input : "&1a."

       0010 0110      // &
          0 0110 001     // 1
0 1100 001  // a
                 0010 1110 // .
                 
output : 011000010011000101110

I/O rules

• input can be any sequence of single byte elements.

• output the resulting sequence of bits in any convenient method, no extraneous bits allowed (0 or 1)

Answer 22

Distributive on myself code-golf kolmogorov-complexity

Answer 23

Validating Words in Word Grids

A follow on from Generating Word Grids

Given a grid of letters, a set of co-ordinates and a dictionary of words, validate that the co-ordinates follow only cardinal direction changes, at least one of the co-ordinates touch an empty space in the centre of the grid, the resulting word is valid given the dictionary (taking into consideration any blank tiles) and return either the grid, with the letters at the co-ordinates removed along with the score of the word, or, if one of the conditions fail, the original grid and a score of -1.

Details

Please detail the format you want to accept coordinates in any reasonable format is acceptable.

Scoring

Letters are worth their values as per Scrabble:

0 points: blank tiles
1 point: E, A, I, O, N, R, T, L, S, U
2 points: D, G
3 points: B, C, M, P
4 points: F, H, V, W, Y
5 points: K
8 points: J, X
10 points: Q, Z

Bonus tiles (indicated by a lowercase letter, or ! for a blank tile) provide a *2 multiplier and stack (eg. if my co-ordinates spell gOLf I would earn (((2+1+1+4)*2)*2), 32 points).

Examples:

Input:

6,4 6,5 5,5 4,5 3,5 3,6 2,6 1,6
UWDESTKP?
ItDBaDEdI
TERMDYTSR
ROANJLEFT
EkCI OOsT
IPAJPGMNY
MZLORITVI
GwEGgPUeI
MNROYOEER

Output:

9
UWDESTKP?
ItDBaD dI
TERMDY SR
ROANJ  FT
EkCI  OsT
IPAJP MNY
MZLO  TVI
GwEGgPUeI
MNROYOEER

(spells RIGOLETE, (1+1+2+1+1+1+1))

Input:

0,3 0,4 0,5 0,6
UWDESTKP?
ItDBaD dI
TERMDY SR
ROANJ  FT
EkCI  OsT
IP  P MNY
MZL   TVI
GwE gPUeI
MNROYOEER

Output:

-1
UWDESTKP?
ItDBaD dI
TERMDY SR
ROANJ  FT
EkCI  OsT
IP  P MNY
MZL   TVI
GwE gPUeI
MNROYOEER

(spells DEST which doesn't appear in the dictionary)

Input:

5,6 4,6 4,7 4,8
UWDESTKP?
ItDBaD dI
TERMDY SR
ROANJ  FT
EkCI  OsT
IP  P MNY
MZL   TVI
GwE gPUeI
MNROYOEER

Output:

12
UWDESTKP?
ItDBaD dI
TERMDY SR
ROANJ  FT
EkCI     
IP  P  NY
MZL   TVI
GwE gPUeI
MNROYOEER

(spells MOsT, (3+1+1+1)*2)

Rules

This is code-golf so the shortest code in bytes wins.

• The order is not important, it can be score then grid, or vice versa.
• Any reasonable format can be used for I/O assuming it is consistent.
• All standard loopholes are forbidden.

code-golf string

---

Questions for meta

Things have changed a lot in the time since I originally posted this, so rather than just posting I thought I'd bump for fredback.

• What would the best way of using an associated dictionary be, taking it as input?
• Obviously the input format for co-ordinates can be more flexible (0-based index, 1-based index, or something) is mentioning this enough?
• Grid input format can be flexible too, mentioning this should be enough too?
• Any other relevant tags?

Answer 24

Crazy Blazin' DOM Injection

I was instructed to post this code golf challenge here for recommendations on how to modify the challenge.

I'd like to tag it.

fastest-code grid and browser , but I don't know how to do that here.

Code golf challenge listed below.

Introduction

This problem is a challenge that has to do with DOM manipulation at scale and overcoming some issues that may be inherent in dealing with the DOM.

• This challenge is interesting because limitations push us to think through things differently and lean on the strengths of languages different than what we usually use.
• I created this challenge myself based on a real world problem I ran into myself (details can be provided if needed). If this challenge has any relation to a differently know problem, those similarities are coincidental.

This challenge will be scored based on fastest execution and fastest algorithm. A multiplier will be given for completing the challege at easy, medium, and hard difficulties.

Challenge

You must render one of the challenge levels in a web browser:

• easy
• medium
• hard

Through any means available to you interacting through a web browser in code you need to complete the following:

1. Get each table displayed and add a class table-n to each table where n is a zero based index of order of the table on the screen. If a table is nested within a table the parent would be N and the child would be N+1 with the next table being N+2.
2. Get each row displayed in each table and add a class of table-n-row-r where r is a zero based index of rows in the table represented by table-n.
3. Get each cell displayed in each table and add a class of table-n-row-r-cell-c where c is a zero based index of cells in a row represented by table-n-row-r.

At the end of the challenge the web page should still be able to be interacted through in the browser, and a call to document.getElementsByClassName('table-n-row-r-cell-c'); should return one and only one cell from the DOM.

Any method available to you as valid as long as:

1. Access to one of the difficulty levels has been done through a web browser
2. The URL of the browser and the page displayed doesn't change
3. A call to document.getElementsByClassName('table-n-row-r-cell-c'); returns only one element

Output Examples

For this example we're using the easy level as input.

The abbreviated output in the DOM should be.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Code Golf Challenge</title>
</head>
<body>
    <table class="table-0">
        <thead>
            <tr class="table-0-row-0">
                <th class="table-0-row-0-cell-0">1</th>
                ...
            </tr>
        </thead>
        <tbody>
            <tr class="table-0-row-1">
                <td class="table-0-row-1-cell-0">11</td>
                <td class="table-0-row-1-cell-1">12</td>
                ...
            </tr>
            ...
    </table>
</body>
</html>

There are only <td> and <th> elements used as cell elements for the challenge.

As long as document.getElementsByClassName('table-n-row-r-cell-c'); returns an element with this class. We're good to go.

Qualifying Entries

All entries that qualify need to have an execution speed of under 40 seconds for any difficulty level.

Timing starts when your algorithm starts, but after the page has loaded completely as all elements must be available (the browser spinner has stopped spinning).

Calculate the runtime for your method by calling performance.now() before and and after your injection method, and subtracting the first from the second as in the example below.

let t0 = performance.now();
doSomething()   // <---- The function you're measuring time for 
let t1 = performance.now();
let totalTime = t1 - t0;

The medium and hard difficulty levels will have their execution time multiplied by 0.50 and 0.25 respectively. None the less, an execution time of less than 40 seconds is needed to qualify. So if the execution time on the medium difficulty was 41 seconds before the multiplier, it does not qualify.

Winner

The winner will be determined by the shortest execution time for dynamic injection of these classes and where document.getElementsByClassName('table-n-row-r-cell-c'); can still be executed against the browser console and return an element where n, r, and c are replaced with indexes.

Answer 25

How wide is this string?

Given a unicode string in any standard encoding of choice, determine how many columns wide it is.

To keep this challenge relatively simple, use the following rules for character widths:

• Tab characters align to the nearest multiple-of-8 column
• CJK characters are 2 columns wide.
  • For the purposes of this challenge, you may assume all characters in Unicode Planes 2 and 3 (U+20000-3FFFF), plus codepoints U+3400-9FFF are CJK characters.
  • CJK characters outside these ranges may be treated as either 1 or 2 columns wide.
• Combining diacritics (U+0300-036F), control characters (U+00-1F, U+7F-9F), and the zero-width space (U+200B) are all 0 columns wide.
  • All other officially zero-width characters may be treated as either 1 or 0 columns wide.
• You may assume that there are no newlines or carriage returns.
• You do not need to handle escape sequences.
• You may assume all other characters are 1 column wide.
  • For any character the standard says has a specific width, you may use that width instead.

Shortest code wins.

---

code-golf string unicode

Answer 26

Tumbling 2x2 in a Matrix

code-golfmatrixinteger

Challenge:

Input: A rectangular integer matrix that's at least 2x2 in size. Output: A 2D integer array, of the result after the top-left 2x2 block has tumbled down.

For example: Let's say we have the following 3x5 matrix as input:

[[ 4, 7,12],
 [11, 2, 5],
 [ 7, 3,15],
 [21,10, 1],
 [12, 6, 6]]

The 2x2 block is [[4,7],[11,2]], which will act as if it was tumbling down from a stairs (in a top-left to bottom-right direction). Here this process step-by-step:

[[ 4, 7,  ],
 [11, 2,  ],
 [--,  ,  ],
 [  ,  ,  ],
 [  ,  ,  ]]

[[  ,  , 4],
 [  ,11, 7],
 [--, 2,  ],
 [  ,  ,  ],
 [  ,  ,  ]]

[[  ,  ,  ],
 [  ,11, 4],
 [--, 2, 7],
 [  ,--,  ],
 [  ,  ,  ]]

[[  ,  ,  ],
 [  ,  ,  ,11],
 [--,  , 2, 4],
 [  ,--, 7],
 [  ,  ,  ]]

[[  ,  ,  ],
 [  ,  ,  ,  ],
 [--,  , 2,11],
 [  ,--, 7, 4],
 [  ,  ,--]]

[[  ,  ,  ],
 [  ,  ,  ,  ],
 [--,  ,  ,  , 2],
 [  ,--,  , 7,11],
 [  ,  ,--, 4]]

[[  ,  ,  ],
 [  ,  ,  ,  ],
 [--,  ,  ,  ,  ],
 [  ,--,  , 7, 2],
 [  ,  ,--, 4,11]]

Doing so, it will add it's values to the other cells in its path. So here is the same step-by-step process with the other numbers added in the cells:

[[ 4, 7,12],
 [11, 2, 5],
 [ 7, 3,15],
 [21,10, 1],
 [12, 6, 6]]

[[ 4, 7,16],
 [11,13,12],
 [ 7, 5,15],
 [21,10, 1],
 [12, 6, 6]]

[[ 4, 7,16],
 [11,13,16],  // Note that the 13 and 5 remain the same, because the cells of the tumbling
 [ 7, 5,22],  // block haven't moved from the previous to this step
 [21,10, 1],
 [12, 6, 6]]

[[ 4, 7,16],
 [11,13,16,11],
 [ 7, 5,24, 4],
 [21,10, 8],
 [12, 6, 6]]

[[ 4, 7,16],
 [11,13,16,11],
 [ 7, 5,24,15],  // Note that the 24 and 8 remain the same, because the cells of the tumbling
 [21,10, 8, 4],  // block haven't moved from the previous to this step
 [12, 6, 6]]

[[ 4, 7,16],
 [11,13,16,11],
 [ 7, 5,24,15, 2],
 [21,10, 8,11,11],
 [12, 6, 6, 4]]

[[ 4, 7,16],
 [11,13,16,11],
 [ 7, 5,24,15, 2],
 [21,10, 8,11,13],  // Note that the 11 and 4 remain the same, because the cells of the tumbling
 [12, 6, 6, 4,11]]  // block haven't moved from the previous to this step

Challenge rules:

• I/O is flexible. You may take the input as integer-matrix, integer list with loose dimension-inputs, as a list of strings, etc. Output can modify the original input, return a new matrix, print space/newline delimiter to STDOUT, etc.
• You may optionally take the dimensions as additional input.

General rules:

• This is code-golf, so shortest answer in bytes wins.
  Don't let code-golf languages discourage you from posting answers with non-codegolfing languages. Try to come up with an as short as possible answer for 'any' programming language.
• Standard rules apply for your answer with default I/O rules, so you are allowed to use STDIN/STDOUT, functions/method with the proper parameters and return-type, full programs. Your call.
• Default Loopholes are forbidden.
• If possible, please add a link with a test for your code (i.e. TIO).
• Also, adding an explanation for your answer is highly recommended.

Test case:

Input:
[[ 4, 7,12],
 [11, 2, 5],
 [ 7, 3,15],
 [21,10, 1],
 [12, 6, 6]]
Output:
[[ 4, 7,16],
 [11,13,16,11],
 [ 7, 5,24,15, 2],
 [21,10, 8,11,13],
 [12, 6, 6, 4,11]]

TODO: More to come.

---

Sandbox questions:

I might change the tumbling process a bit later on, since I'm not too happy about the current one. I still want the tumbling 2x2 down the matrix, but I might make the way the other values changes a bit different. This is just an initial idea.

• Any missing tags?
• Any missing rules?
• Any suggestions on how to change the output without changing the core part of the tumbling top-left 2x2 block?
• Any suggested test cases?

Answer 27

Trapping a Jogger

A person starts jogging to the right from his house on a busy street.

t=0
0 1 2 3 4 5 6 7 8 9 A B C
⌂ - - - - G - - G - - - G
>

He travels 1 hectometer every minute, so he is 11 hectometers away from his house after 11 minutes:

t=11
0 1 2 3 4 5 6 7 8 9 A B C
⌂ - - - - R - - R - - - G
                      >

Since this is a busy street, there are walking signals that occasionally turn red. In this example, the signals at 5, 8, and 12 units from home alternate colors every 2, 10, and 4 minutes (this would not be a fun road to drive on). The signals are red (signal stop ✋) for the same duration that they are green (signal go 🏃).

Our jogger doesn't want to wait long, so he instantly turns around when he reaches a stoplight that is red, even if it will turn green within the next minute.

t=12
0 1 2 3 4 5 6 7 8 9 A B C
⌂ - - - - G - - R - - - R
                        >

t=12.001
0 1 2 3 4 5 6 7 8 9 A B C
⌂ - - - - G - - R - - - R
                        <

t=13
0 1 2 3 4 5 6 7 8 9 A B C
⌂ - - - - G - - R - - - R
                      <

This can cause the jogger to reverse direction again, making for a potentially long outing.

t=16
0 1 2 3 4 5 6 7 8 9 A B C
⌂ - - - - G - - R - - - G
                <      

t=16.001
0 1 2 3 4 5 6 7 8 9 A B C
⌂ - - - - G - - R - - - G
                >      

View the rest of the sequence using a visualizer.

Task

Given the cycle intervals and positions of a list of streetlights, determine the time until the jogger returns to his house (at distance 0) or runs to the right of the rightmost streetlight.

The streetlights at time t=0 will all have just turned green.

The n cycle intervals shall all be integers at least 2. The n positions of the streetlights may be taken as either (sorted) absolute distances from home or the distance from that streetlight to the previous. In the example, this would be either [5,8,12] or [5,3,4].

Example cases

positions
intervals
output

5,8,12
2,10,4
38

10
20
11

10
6
20

2,8
8,6
40

2,8
7,6
16

1,2,3,4,5,6
6,5,4,3,2,1
16
```

Answer 28

International "Hello, World!" (WIP) code-challenge string

(Please note the special scoring for this challenge)

This code-golf question has over 900 answers and all of them print "Hello, world!" in English! If we can use hundreds of different programming languages to print that message, why can't we use hundreds of different natural languages to express that message?

Task & scoring

Your task is to beat the answers of the Hello, world! challenge ("HW" challenge from now on) in different natural languages, as determined by the length ratio of the English string "Hello, world!" and the string in the natural language you pick. For example, I could pick Portuguese, hence I will have to print "Olá, mundo!" which has a length ratio of 11/13.

• if your natural language has capitalization, you must respect the original capitalization.
• if your natural language has punctuation, you must respect the original punctuation.

Then you pick the programming language you are going to write your code in. For example, I could pick Python. And you write your program. My program could be print("Olá, mundo!"), with a standard code-golf score of 20.

You then look for the best submission in the HW challenge with the same programming language you chose, let's say it has score S. (We probably need a leaderboard for challenge HW to make this step easier.) My score would then be (20/S)/(11/13).

Does this make any sense? Any preliminary feedback?

Answer 29

Extract an integer from another

This is a somewhat interesting problem I ran into while nanboxing: given two integers, compute their bitwise-AND and concatenate the resulting "substrings" into a new integer.

More precisely: you are provided two integers as input — an input integer and a bitmask. As output, you should produce the bitwise-AND of the two such that, given a mask with \$n\$ set bits, the corresponding bits from the input are grouped together in the first \$n\$ bits of the resulting integer.

The following pseudocode is one way to implement the function:

-- x and mask are lists of booleans
function (x, mask)
  local result=list();
  for i=1, min(x.length, mask.length) do
    if mask[i] then
      result.append(x[i]);
    end
  end
  return result;
end

Example inputs and outputs

// In binary:
// f(x, mask) == result
f(1011, 1111) == 1011 // Select entire number
f(1010, 1010) == 11   // Select bits 1 and 3, and concatenate them
f(11001100, 01100110) == 1010 // Concatenate substrings [1:2] and [5:6]
f(11111111, 10101010) == 1111 // Concatenate bits at odd indices.

// 16-bit variants in hexadecimal:
f(BEEF, 1111) == 9
f(DEAD, 8888) == F 
f(1337, FF00) == 13
f(CODE, 7777) == 82E

// Two 64-bit variants (in hex):
f(400921FB54442D18, CODE601F15DABE57) == 111DE42C8
f(FFFE0000004010CC, 8003000000000000) == 6

Specific rules

• Standard loopholes, default IO, etc. apply where not overridden.
• Input and output values must fulfill \$x \in \{b_{set}, b_{unset}\}^{n}\$ for some \$b_{set} \neq b_{unset}, n \in \mathbb{N}_{\geq 16}\$ of your choice. In other words:
  • You must support integers of at least 16 bits in your representation, but you may otherwise arbitrarily constrain their size - i.e. to 32-bit integers. You may also accept integers of any length through lists, arrays, strings, etc.
  • The "set" and "unset" values do not need to be of the same type or length, but they must be constant and distinct.
  • Most "linear" representations for integers are valid: integers, vectors, arrays, strings, etc.
• This is code-golf, so the shortest answer in bytes wins.
• Have fun!

Answer 30

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(shading, (solid; empty; striped)).
feature(color, (red; green; purple)).
feature(shape, (oval; diamond; squiggly)).
dimension(D) :- feature(D, _).
card(c(N,F,C,S)) :-
    feature(number,N); feature(shading,F); feature(color,C); feature(shape,S).
property(c(N,F,C,S),number,N) :- card(c(N,F,C,S)).
property(c(N,F,C,S),shading,F) :- 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"