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

Posting

To post to the sandbox, scroll to the bottom of this page and click "Answer This Question". Click "OK" when it asks if you really want to add another answer.

Write your challenge just as you would when actually posting it, though you can optionally add a title at the top. You may also add some notes about specific things you would like to clarify before posting it. Other users will help you improve your challenge by rating and discussing it.

When you think your challenge is ready for the public, go ahead and post it, and replace the post here with a link to the challenge and delete the sandbox post.

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
• Comments addressing specific points mentioned in the proposal
• Problems that could make the challenge uninteresting or unfit for the site

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

Simon says "Make me a game"

code-golf graphical-output game

Forked from this closed question.

Create a "Simon says" game.

Take an input \$n\$, for number of levels, and \$k\$, for number of buttons and do the following:

• Create a square area for the buttons.(at least 100x100 pixels in size.)

• Divide it into k rectangular buttons of equal size. k will always be even.

• Each button should be of a different color, and none of them should be the same color as the background.

• The game should proceed as follows:

  • Starting level is 1. Level number should be displayed at the top.

  • Get a random order in which the buttons should "light up". The number of clicks should be level number + 4.

  • In that same sequence, display a visual indicator on each button, so the user knows what order they should click the buttons in.

  • There should be at least a 200ms delay between each visual indication.

  • If the user clicks them in the correct order, move on to the next level, and repeat the above steps. Otherwise, display "Game Over" at the bottom of the screen.

Here is a playable demo for k=4, Courtesy of Gabriele D'Antona.

---

Meta

• Is this specification clear?

• Any thoughts/feedback?

• Should there be a limit on the values of n and k?

Answer 2

Animal-Alphabetical Sequence

Answer 3

Answers made up from older answers

answer-chaining decision-problem

---

In this challenge, your task is to take a number as input, and determine whether it is the number of previous answers. For example, the third answer would print/return a truthy value is given 2, and a falsey value for any other input.

However, all answers must be made up of previous answers. For example, if the existing answers were +1, t()==1, and _=>inpu, some allowed answers would be:

• t()==1+1
• _=>input()==1+1
• +1+1+1+1
• ​

Examples of answers that would not be allowed:

• 1+
• 1+1
• _=>+1

• ​
  

  (newline)

For the output/return format, this is a list of the allowed formats I'll use for this challenge.

Scoring and initial allowed parts of answers coming soon.

Meta

• What should the title be?
• Any recommended initial allowed parts?
• Is this easy to read/understand?

Answer 4

Implement ASCII -> GSM-7 (SMS) text packing

SMS messages can store 160 ASCII characters into 140 characters. It does this by chopping off the top bit from each byte and packing them together.

The simplified steps:

1. Convert the string to binary little endian ASCII.
2. Remove the top bit from each byte.
3. Pack them together so there are no gaps.
4. If applicable, pad the final byte with zero bits.

So, take the text "Test0123".

First, we convert it to little endian binary.

0x54     0x65     0x73     0x74     0x30     0x31     0x32     0x33
00101010 10100110 11001110 00101110 00001100 10001100 01001100 11001100

Then, we chop off the last (most significant) bit of each octet:

0010101  1010011  1100111  0010111  0000110  1000110  0100110  1100110

Then, we pack them together into a 7 byte array:

0xd4     0xf2     0x9c     0x0e     0x8b     0xc9     0x66
00101011 01001111 00111001 01110000 11010001 10010011 01100110

In the case of bitwise operations, it is a simple funnel shift.

The basic algorithm in C is here for an 8 byte ASCII string. However, your algorithm must accept any length.

void ascii_to_gsm7_8_bytes(uint8_t *buf, const char *str)
{
    buf[0] = (str[0] >> 0) | (str[1] << 7);
    buf[1] = (str[1] >> 1) | (str[2] << 6);
    buf[2] = (str[2] >> 2) | (str[3] << 5);
    buf[3] = (str[3] >> 3) | (str[4] << 4);
    buf[4] = (str[4] >> 4) | (str[5] << 3);
    buf[5] = (str[5] >> 5) | (str[6] << 2);
    buf[6] = (str[6] >> 6) | (str[7] << 1);
}

The input can either be a string (optionally with a provided length) or an input from stdin which is terminated with a newline or EOF.

The string will be a non-empty printable ASCII string that is 160 bytes or less. It is safe to assume that all bytes are 0x20 <= x < 0x80, meaning the last MSB bit is cleared beforehand.

Important: While strings can be null terminated, you are not allowed to use that null terminator for padding the last byte.

Output will be the packed string.

The output can either be printed as a list of values (base 10 or base 16) to stdout or returned in an output array.

Test cases (output is in hex):

Input text -> Output (hex)
"" -> Empty strings do not need to be handled.
"Úñíçódé" -> Unicode does not need to be handled, only ASCII.
"Hi!" -> {0xc8, 0x74, 0x08}
"Test0123" -> {0xd4, 0xf2, 0x9c, 0x0e, 0x8b, 0xc9, 0x66}

More test cases will be added if this is accepted.

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

Answer 5

Isosceles triangle truncations

Most triangles are not isosceles. Here is an example:

A ____ C
 |   /
E|  /
 | /D
 |/
B

However, we can cut this triangle into two smaller triangles, one of which is isosceles. We can do this in a number of ways:

• By cutting from C to E, we create isosceles triangle BEC. (Due to limitations of ASCII art, you'll just have to imagine that E is in the correct place.)
• By cutting from A to D, we create isosceles triangle ADB.
• By cutting from A to D, we create isosceles triangle ADC. (This always happens for right-angled triangles, of course. It's hard to draw ASCII art triangles that are neither right-angled nor isosceles.)

Each triangle can be derived in turn from the original triangle by fixing one of the three sides (which will be the base of the new triangle) and the smaller of the two adjacent angles, adjusting the other base angle as necessary.

Your challenge is, given a triangle of three points A, B and C in any reasonable format, is to output at least one of its isosceles triangle truncations.

It must be possible to obtain all three truncations for a given triangle. This is typically achieved by permuting the parameters of the function, but you can use some other input method if you wish. In any case please indicate how to obtain all truncations.

Example: For an input of (0, 0), (0, 4) and (8, 0), the output might be (0, 0), (4, 2), (8, 0); (0, 0), (0, 4), (4, 2); (3, 0), (0, 4), (8, 0). Alternatively, the output might just be (3, 0), and to obtain (4, 2) you would have to input the triangle in a different order.

You may assume that the input triangle is not isosceles (or equilateral, for those languages that allow parameters that are surds rather than floating-point decimals). For instance, for programs that normally output all truncations, they might simply return a single equilateral triangle unchanged.

Your method should be theoretically exact even if the code suffers from floating-point limitations.

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

Answer 6

possible chess moves in choice format

chess fastest-code the goal is to make a function that takes in a board in choice format and color and outputs all possible moves.

for example: ['pawn',1,1] -> ['pawn',1,2], ['pawn',1,3].

Answer 7

Divisor chains

Definition

A simple path in the divisor graph of {1,...,n} is a sequence of distinct numbers between 1 and n such that if k immediately follows m, then either k divides m or m divides k.

Task

(1) Return a list of integers that represents the lexicographically earliest longest, simple path in the divisor graph of {1,...,n}.

Implement a named function with one argument, f(n), n a positive integer; you can assume n <= 33. The function takes the argument for input.

No print statements (or other I/O-statements) are allowed in the function; the return is a list (or tuple or array). The use of external library functions is not allowed.

(2) A print statement that prints the output of (1): print(f(n)). The function name print is not obligatory and the print function can use standard libraries.

Test

(1) For n = 10 the call f(10) returns [4, 8, 1, 5, 10, 2, 6, 3, 9].

(2) print(f(10)). We do not fix the format of the returned list. The output might also look like 4 8 1 5 10 2 6 3 9 or any other convenient way.

Challenge

This is code-golf with restricted-time, so the shortest code in bytes wins if it can run the test above on TIO https://tio.run/ without timing out. Only the code of the generating function f is counted, without the print statement.

Tags: code-golf, restricted-time, math, sequence

Answer 8

Lazy Robot Monkey Problem

Question Summary

You have made a robot monkey. The purpose of the robot is to move through the trees and try to reach as many as possible monkeys before running out of battery. You have to follow some rules while moving.

You are give a interlinked tree in the following format :

Here each 1 is a monkey and each 0 is an empty place.

Each note can have multiple parents and Childs but unlike a Graph its direction is downward.

The robot monkey has a initial energy value.

The robot Monkey can move through the nodes following certain rules:

• Going up to the parent node needs 4 units energy.
• Going down to the child node needs 2 units energy.
• There may be some food at some nodes. Each times the monkey eats its energy increases by food value.
• The monkeys energy can never be negative.
• The monkey cannot eat more than the initial energy value.

What to do?

You are given the initial node (where your robot monkey is initially sitting).

The node is in the following format :

class Node:
    parents = [] # Will have all the parents
    children = [] # Will have all the children
    isMonkey = 1 # May be 0
    foodValue = 0 # May be anything

You are also given a initial food value and the number of monkeys in the tree.

You now have to find how many monkeys can you maximum meet with before your battery dies.(by going to the same position)

Your answer should be in format:

def monkeyMeet(initialNode, energy, totalMonkeys):
    # write your code here
    pass

Or in any other programming language.

The size of the tree may be huge.

Answer 9

SimpleHearts KOTH

SimpleHearts

SimpleHearts is a four player trick-taking card game similar to Hearts, with a few simplifications. Hearts has several possible rule variations, and the rules I will use are outlined here.

For each game, each of the four players are dealt 13 of the cards in a standard deck. After that, there will be 13 "tricks", and during each trick the players will take turns playing exactly one of their cards. Each trick will consist of the following:

• One player leads the trick by playing a card. The suit of this card is the "led suit". On the first trick the player with the 2 of clubs must lead with the 2 of clubs, on the following tricks whoever won the previous trick will lead.

  The leader may not lead a heart until another player has played a heart or the Qs (Queen of Spades). Exception: if the leader only has hearts in their hand, they may lead one of their hearts. The leader may lead the Qs at any time.

• In a clockwise fashion, each player will take their turn playing one card in their hand of the led suit. If the player has no cards of the led suit, they may play any card. Exception: On the very first trick, no one after the leader may play a heart or the Qs, unless all of their cards are hearts or the Qs (obviously absurdly unlikely).

• After all four players play a card, whichever player played the highest value card of the led suit wins the trick. Ace is highest value and 2 is lowest. The winner of the trick receives 1 point for every heart played by anyone in the trick, and 13 points if the Qs was played in the trick.

• Repeat, with the winner leading the next trick.

The objective of the game is to receive as few points as possible. After all 13 tricks are played, the score of each player is the total number of points they took during gameplay. Important exception: if one player takes all possible points, i.e. the 13 hearts and the Qs, they receive 0 points and all other players receive 26 points (this is called "shooting the moon").

Key differences from standard Hearts:

• There is no passing cards

• Scores are not cumulative in the standard way (the scoring system of this particular challenge will be explained next).

Gameplay and Scoring

This is a KOTH challenge, meaning the objective is to create a bot (in this case a Python function) which will compete against other submitted bots in the game of SimpleHearts. All subsets of size 4 of the set of submissions will play against each other in N matches of 4 games each. For sandbox: N is tbd, should be as high as reasonably possible.

The dealing of the cards will be identical in each of the 4 games in a match, except rotated. For example, suppose the players are A, B, C, and D. In the second game player B will have the same hand player A had in game 1, C will have B's game 1 hand, etc. This is to reduce the impact of random chance, as one player being dealt a bad hand will affect all players equally in theory.

Each submission's final score will be the sum of their scores in all the games they played. The winner will be the submission with the lowest final score. In the case of a tie, the oldest submission will win.

Technical Requirements

Each submission will be a Python function (for sandbox: this is an arbitrary choice, is there a better one?) which takes as parameters:

• A list of 2-tuples representing the cards in their hand. Each tuple will be of the form (12, 's') with the number representing the value of the suit and the string representing the suit, being one of s, h, d, c. For simplicity's sake the numbers are from 2 to 14, and we do not care about encoding "Queen" or "Ace". Therefore the Queen of Spades is (12, 's'), Ace of Diamonds is (14, 'd'), and the 2 of clubs is (2, 'c').

• A list of 4 integers representing the scores of each player so far in the current game. The first element of the list is your score, then the player to your left, then the player across, then the player to your right.

  Note: leading with hearts is allowed if and only if you only have hearts, or someone has a nonzero score.

• A list of 4 lists of tuples representing which cards have been played and by whom. The first list will be the cards you played, in order. The second list will be the cards played by the player on your left, in order. Etc.

• A list of 0-3 tuples representing the cards that have been played in the trick, in order.

As output, the submission must return a single tuple representing a card in its hand, which is legal to play according to the rules of SimpleHearts. Of course, the function may choose to ignore any of these inputs but if it makes an illegal output, it is disqualified. In testing, I will force whoever has the 2 of clubs to lead with it on the first hand, ignoring the contents of the function.

The submission must be deterministic, i.e. will always produce the same output on the same input (so pseudorandom numbers with a set seed are allowed).

All submissions must be at most 100 000 characters.

The challenge will end 14 days after this prompt is posted, after which I will test all valid submissions against each other in the manner I described.

For sandbox

This prompt is still WIP, but I appreciate any comments. I intend to create a controller and some example submissions, but only after Sandbox folk deem the challenge to be good enough.

Is there any reasonable way to make the requirements easier or the game simpler? Cause this post is kinda long.

Answer 10

The UTM theorem

Let ℕ denote the set of natural numbers. Let A × B denote the Cartesian product of A and B. Let A ⇀ B denote the set of partial functions from A to B.

The UTM theorem says that there exists a computable function u : ℕ × ℕ ⇀ ℕ such that, for every computable function f : ℕ ⇀ ℕ, there exists a p : ℕ such that, for every x : ℕ, u(p, x) ≃ f(x). That is, there exists a universal computable function (analogous to the universal Turing machine).

Implement such a function in your language. Shorter is better.

Example: Python (57 chars)

lambda p,x:eval(p.to_bytes(p.bit_length()//8+1,'big'))(x)

Answer 11

Radical of an integer math code-golf

The radical of an integer (written as \$\mathrm{rad}(n)\$) is defined as the product of all prime numbers that divide it. This it A007947.

For example, since \$ 504 = 2^3 \cdot 3^2 \cdot 7 \$, \$ \mathrm{rad}(504) = 2 \cdot 3 \cdot 7 = 42 \$.

Challenge

Your task is to write a function or a program which takes a number as the input, and output its radical.

• You can take/output the numbers in any format allowed by the default I/O rules

You don't have to handle any cases where the input isn't an integer or isn't positive (you don't have to handle 0).

Test cases:

504 -> 42
6 -> 6
57 -> 57
1024 -> 2
9 -> 3
1 -> 1

This is code-golf, so the shortest answer in bytes wins. Good Luck!

Answer 12

Cosmic ray hacking

code-golf cops-and-robbers kolmogorov-complexity atomic-code-golf

Cosmic background radiation can cause random bit flips in electronics. For this reason, some mission-critical computers undergo radiation hardening. Your task is to use your magic bit flip gun to hack in to a program and make it print something different.

Cops' challenge

• Write a program or function that outputs a determinate, non-empty string of your choice (which you should specify).
• Choose a different, determinate string of your choice (which you should specify).
• Also specify a number n which is the number of bit flips the robbers should perform on your answer in order to get it to output the second string.

Rules

• Standard IO rules apply
• This is code-golf, so shortest uncracked program wins.

Robbers' challenge

Choose an uncracked cop submission written by another user. Find a program that differs by exactly n bit flips from the original cop's program, and outputs the string s (where n and s are specified by the cop). First valid crack for each cop answer wins.

Rules

• Your program must be written in the same language and version as the cop's
• Your program must use the same I/O method as the cop's, unless they specify otherwise
• Flipping the same bit twice (which does nothing to the whole string) is allowed, but it takes up 2 of your available bit flips.

Example

Cops - Python 3, 8 bytes

Prints 5.

print(5)

Using 1 bit flip, change this program to print 4.

Robbers - Cracks example answer

print(4)

Because the ASCII digit 5 is 00110101, and 4 is 00110100 (the last bit has been flipped)

---

Meta

• Should I change the scoring system?
• This is related to radiation-hardening, but I don't think it actually is. Is this right? Or maybe source-layout or restricted-source would be better? (radiation-softening?)
• atomic-code-golf refers to the limit that the cop imposes on the robber, rather than the scoring system - is this an acceptable use of the tag?
• Is this clear enough?
• Is this a duplicate of an existing challenge?
• Any other feedback?

Answer 13

Write a Brainfuck compiler + decompiler!

Many Brainfuck compilers will convert to a different language instead of compiling directly.

Your job is to write not only a compiler in language X which compiles Brainfuck to the same language as the compiler, but also a decompiler which takes code compiled with said compiler and outputs equivalent Brainfuck.

Rules

• No embedding the original/stripped source code or similar loopholes. You know what I mean.
  • Additionally, no outputting an interpreter with the original source code.
• The compiler must accept whitespace and comments
• Optimizations are allowed and encouraged, as long as you can convert these back to Brainfuck.
• The input will always be a valid Brainfuck program
• You are not required to print comments in the decompiler, however, excess comments and whitespace are allowed in the output as long as the program is valid. However, these lower your score. 🙂
• You do not need to handle excess whitespace or comments in the decompiler, you can assume it was code directly generated by your compiler.
  • Therefore, it is also guaranteed to be valid code.
• No executing the compiled code.
• The compiler must generate correct code and run without any helpers.
  • You are allowed to be flexible with the cell size as long as it is at least 8 bits.
  • You are allowed to be flexible with the tape size as long as it is at least 30,000 elements. A wrapping tape is not required.
  • EOF can store either 0, -1, or leave unchanged

Your score will be the following:

(compiler size in bytes + decompiler size in bytes) × (compiled size of factor.bf in bytes ÷ size of factor.bf in bytes)

This is popularity-contest, so the most votes wins. This is because there can be some creative and boring solutions. Golfing is still encouraged.

Answer 14

Introduction

This challenge was originally the "Among Us" challenge in the "Misc" category of YASCON CTF 2020. (The link includes an answer to that challenge. Click at your own risk.)

You're given a lot of files, only 1 of which is different from every other files. Your job is to find that 1 different file.

Challenge

• Input: the file names of all the files to be searched through.
• Output: the name of the 1 different file.

Avoid burying the important details of your challenge in a mound of unimportant details. Be concise. Include what needs to be included.

It is guaranteed to have $n+1$ files, of which $n \ge 2$ files are the exact same, and 1 different file.

This is a code-golf. Least bytes wins.

Example Input and Output

Input:

1.txt 2.jpg 3.png 4.mp3

Output:

(3.png is different)

3.png

Answer 15

Create a playable, unbeatable Tic Tac Toe game

The challenge is to write the smallest possible Tic Tac Toe game where the opponent is an unbeatable AI. The requirements are as follows:

• The opponent should be an unbeatable AI (self-playing opponent that can't lose)
• The game should be able to detect win/draw/loss and end if this happens (without crashing)
• The input should be the player move (square index or something like that)
• The game should be able to handle invalid input and act appropriate if this happens (ask for input again)
• The game must be displayed graphically on a classic 3x3 format with X:s, O:s and empty squares. The display should be in line vertically and horizontally, se below examples. The display needs to happen after at least every human move to be able to follow the progress.

As long as these conditions are fulfilled you are free to solve it in any way you'd like.

Rules of Tic Tac Toe: Each player (X and O) takes turn placing their marker on the 3x3 board. The game ends in a win if the player gets 3 in a row, loss if opponent gets 3 in a row, and draws if the board gets full.

Challenge winning criterion: Smallest code in bytes.

Example view of a valid input/output gameplay:

[' ', ' ', ' ']
[' ', ' ', ' ']
[' ', ' ', ' ']

Your move: 3
[' ', ' ', 'X']
[' ', ' ', ' ']
[' ', ' ', ' ']

[' ', ' ', 'X']
[' ', 'O', ' ']
[' ', ' ', ' ']

Your move: 6
[' ', ' ', 'X']
[' ', 'O', 'X']
[' ', ' ', ' ']

[' ', ' ', 'X']
[' ', 'O', 'X']
[' ', ' ', 'O']

Your move: 8
[' ', ' ', 'X']
[' ', 'O', 'X']
[' ', 'X', 'O']

['O', ' ', 'X']
[' ', 'O', 'X']
[' ', 'X', 'O']

Example of invalid gameplay (not horizontally or vertically in line and not using X and O as markers, which makes it hard to see what is going on):

Your move: 4
[, , ]
[0, , ]
[, , ]

[1, , ]
[0, , ]
[, , ]

Your move: 9
[1, , ]
[0, , ]
[, , 0]

Suggested tags: tic-tac-toe, code-golf

Answer 16

Ratios to Ben Johnston's Notation

music code-golf

Given a just intonation ratio, express it as a note name in Ben Johnston's notation relative to C.

You can take your input as a rational number (if your language has a rational type) or as a pair of integers. You have to handle ratios with a prime limit of 19, or in other words, ratios whose prime factorizations don't contain any primes above 19.

Use the following characters for the accidentals:

+ - 81/80
# b 25/24
7 L 35/36
^ v 33/32
13 _13 65/64
17 _17 51/50
19 _19 95/96

Output them in the following order:

• 7, ^, 13, 17, 19
• #, b
• L, v, _13, _17, _19
• +, -

7, 13, 17, and 19 should be separated by commas when they occur adjacently in order to avoid ambiguity.

Test cases:

1/1 -> C
2/1 -> C
3/2 -> G
4/3 -> F
5/4 -> E
5/3 -> A
6/5 -> Eb
7/4 -> B7b
7/5 -> G7b
9/5 -> Bb
9/8 -> D
10/9 -> D-
11/8 -> F^
16/9 -> Bb+
17/16 -> C17#
21/16 -> F7+
25/24 -> C#
32/27 -> Eb-
34/19 -> A17_19#
78/77 -> C13Lv
81/64 -> E+
160/147 -> C#LL-
323/280 -> D17,19L-
416/405 -> D13bb-
441/440 -> Db7v+
1029/1024 -> Db777+
6144/6125 -> CbLL-
531441/524288 -> B#+++
4194304/4117715 -> A#LLLLLLL---

Answer 17

Find all enharmonic equivalences of an arbitrary EDO

music code-golf

Given integers n and s, print all pairs of enharmonically equivalent pitch classes in n-EDO, such that each note of a pair has at most s sharps and flats.

Note names are assigned such that F, C, G, D, A, E, and B form a chain of n-EDO's best approximation to 3/2 (that is, \$n \log_2(3/2)\$ steps, rounded to the nearest integer, or the "fifth"). "#" adds seven fifths, and "b" subtracts seven fifths; you can have as many of one as you want or none at all. (Note that in some EDOs, such as 24, there are some pitches that can't be written with only sharp and flat accidentals.)

Note that C# = Db means the same thing as Db = C#. Your code should output only one of these, but which one you output is up to you.

Be prepared to handle these situations:

• # and b might not raise or lower the pitch
• # might lower the pitch
• E and F might be the same note
• F might be lower than E

Your code should work for at least all integers n in [1, 200] and all integers s in [0, 50].

Test output

(12, 1)

F# = Gb
Fb = E
F = E#
C# = Db
Cb = B
C = B#
G# = Ab
D# = Eb
A# = Bb

(19, 1)

Fb = E#
Cb = B#

(19, 2)

F# = Gbb
F## = Gb
Fbb = E
Fb = E#
F = E##
C# = Dbb
C## = Db
Cbb = B
Cb = B#
C = B##
G# = Abb
G## = Ab
D# = Ebb
D## = Eb
A# = Bbb
A## = Bb

(22, 2)

Fbb = C#
Fb = C##
F## = Bbb
Cbb = G#
Cb = G##
Gbb = D#
Gb = D##
Dbb = A#
Db = A##
Abb = E#
Ab = E##
Ebb = B#
Eb = B##

(31, 3)

Fbbb = D#
Fbb = D##
Fb = D###
F## = Abbb
F### = Abb
Cbbb = A#
Cbb = A##
Cb = A###
C## = Ebbb
C### = Ebb
Gbbb = E#
Gbb = E##
Gb = E###
G## = Bbbb
G### = Bbb
Dbbb = B#
Dbb = B##
Db = B###

(32, 3)

F## = Dbbb
F### = Dbb
Fbbb = A#
Fbb = A##
Fb = A###
C## = Abbb
C### = Abb
Cbbb = E#
Cbb = E##
Cb = E###
G## = Ebbb
G### = Ebb
Gbbb = B#
Gbb = B##
Gb = B###
D## = Bbbb
D### = Bbb

(53, 4)

F#### = Dbbbb
Fbbbb = A###
Fbbb = A####
C#### = Abbbb
Cbbbb = E###
Cbbb = E####
G#### = Ebbbb
Gbbbb = B###
Gbbb = B####
D#### = Bbbbb

(5, 0)

F = E
C = B

(7, 1)

Fb = F
Fb = F#
F = F#
Cb = C
Cb = C#
C = C#
Gb = G
Gb = G#
G = G#
Db = D
Db = D#
D = D#
Ab = A
Ab = A#
A = A#
Eb = E
Eb = E#
E = E#
Bb = B
Bb = B#
B = B#

(9, 1)

Fb = G
F = G#
Fb = A#
F# = Eb
Cb = D
C = D#
Cb = E#
C# = Bb
Gb = A
G = A#
Gb = B#
Db = E
D = E#
Ab = B
A = B#

(11, 1)

F# = Db
Fb = A
F = A#
C# = Ab
Cb = E
C = E#
G# = Eb
Gb = B
G = B#
D# = Bb

(13, 1)

F# = Cb
Fb = B
F = B#
C# = Gb
G# = Db
D# = Ab
A# = Eb
E# = Bb

Answer 18

Implement bottom (encode)

Answer 19

Is the Skat null game safe? [WIP] skat code-golf

For everyone who knows the card game Skat. Did you ever wondered when playing a null game: is this really safe to win regardless the other player cards? Well, let's try to solve this question with code.

The Skat game

Skat is card game with 32 cards. There are four colours: Diamonds ♦️, Hearts ♥️, Spades ♠️ and Clubs ♣️. Each colour has: Ace, King, Queen, Jack, 10, 9, 8 and 7. Three players are playing, so each one get 10 cards. The remaining two cards are called Skat and remain covered. Before each game it is to decide which of the three players plays alone against the other two which play together. The alone player gets the possibility to exchange one or two of his cards against one or two of the covered cards in the Skat. More about Skat can be read on Wikipedia.

The null game

There are times when get so bad cards, i.e. no Aces and no Jacks, that they will indeed really good, namely when you can't make any points, not even a trick with the cards.

The task

Write a program that will determine if an input of ten cards of the 32 cards will guarantee that the player will win the null game, i.e. the player won't get any tricks regardless how the other 22 cards are distributed for the other two players and whether or not the alone player is in forehand. You can assume any reasonable input and output that suits you. For convenience a reasonably sorting of the cards can also be assumed.

One note to the forehand rule: it is assumed that the alone player wants to win so he or she won't sabotage the game with drawing an Ace or similar high cards.

Test cases

Let's assume an array of two character strings where the first represents the colour (D for Diamond, etc.) and the second the value (7, 8, 9, X, J, Q, K, A) E.g ['D7','D8','D9','H7','H8','C7','C8','CX','CQ','CA'] will result in true indicating that this null game cannot be lost.

[more to come]

This is code-golf so the shortest code wins.

Answer 20

Colorize a diff, unified format

Answer 21

Catch the fruit (Abandoned) graphical-output game

I feel that this is too complex to be a good code-golf question, and has too many things to specify for it to be anywhere near serviceable. Anybody willing to make this idea into a proper question can do so.

Implement a osu!catch style game.

Introduction

osu!catch is a rhythm game where the player moves a "basket" to catch "fruits" falling from the top of the screen to the beat of a song. Think pong, but with timing.

It is highly recommended to watch this video before reading the question.

Here's a gameplay example from Bubbler: [osu!catch] Hitsuji to Ojisan - XENO [Spec's Overdose]

Input

You are required to take the following inputs:

• Time: How long your program is supposed to run.

• Approach Rate: This is the speed at which the "fruits" are supposed to fall down.

• Beatmap: An array of [time, x position, value] triplets where:

  • Time: you must support time in seconds, at the very least. Higher precision is encouraged.
  • X position: Where it will fall from.
  • Value: The size of the "fruit" will decrease with it's value.

Gameplay

Play area

• The canvas must be in a 4:3 aspect ratio.
• The score must be displayed at the top of the screen, in the middle. You do not need to align it.
• The score starts at 0.
• Use a dark background(#222222, preferably).

The player

• The player must be of a rectangular shape, white in color.
• Height: 1/50 of canvas height, Width: 1/6 of canvas width.
• The player must be at the bottom of the screen, movable using any two keys of your choice.
• The player must have a "dash" button. Their speed must increase 0.5x when they hold the dash button.
• When the player collects a fruit, it must disappear, and it's value must be added to the score.
• When the player misses a fruit, there should be an indicative visual cue where the fruit fell.(a small red square, preferably)
• The player must be constrained within the canvas.

Fruits

• Fruit must be square in shape, and red in color.
• Fruits must fall from the top of the screen, outside the viewport(unless unsupported).
• Max fruit size is 0.1 × height. Size scales inversely with value.
• Fruit speed must be related to the approach rate i.e. Higher approach rate must make the fruits fall faster. You may do this however you like, but please be reasonable.
• The lower edge of the fruit must touch the bottom of the screen at it's time value.

Scoring

This is code-golf. Shortest answer in each language wins.

---

Meta

• Is the specification simple enough?
• I am planning on making a separate ascii-art challenge for this. Is that a better idea?
• Is the specfication clear?
• Any further feedback?

Answer 22

Which Ninjutsu am I casting? code-golfstring

Posted

Answer 23

Trilobaccis' speed

The challenge is inspired by this beautiful one: Speed of Lobsters. And it's similar to this other one: Is it a lobster number?.

The word Trilobacci is a blend of Tribonacci and Lobster.

About tribonacci, quoting Wikipedia:

The tribonacci numbers are like the Fibonacci numbers, but instead of starting with two predetermined terms, the sequence starts with three predetermined terms and each term afterwards is the sum of the preceding three terms.

Regarding lobsters and speed, they refer to this subreddit where people have fun editing the text of images to create new phrases.

The challenge

The challenge is to "blank out" the digits of given numbers (let's say a,b,c) using the digit of other numbers (say x,y,z) which you have to find by yourself, and then tell whether you could use all the digits from x,y,z to blank out some (or even all) of the digits from a,b,c.

Being more specific: given three positive integers in ascending order, which are necessarily part of a tribonacci sequence (at least the one they can generate), find the three numbers that generated the sequence and use them to blank out the original input numbers according to the lobsters rules.
Then output a truthy value if you used all the digits from the found numbers, or a falsy value if you are left with digits that couldn't be used to blank out the input digits.

For the numbers generating the sequence, I mean the the three smallest non-negative integers being part of the sequence.

Lobsters rule!

Start taking the first digit of the first number of x,y,z and blank out its first occurrence in the digits of a,b,c. Then proceed with the next digit from x,y,z looking for its first occurrence in a,b,c, starting from where you left.

Examples

Given

[ 13, 23, 43 ]

you'll find out that they are part of a sequence generated by

[ 1, 3, 3 ]

so then you can proceed at the speed of lobsters:

[ 1, 3, 3 ]   --->   [ 13, 23, 43 ]
               ||
              _||_
              \  /
               \/
[ X, 3, 3 ]   --->   [ *3, 23, 43 ]

[ X, X, 3 ]   --->   [ **, 23, 43 ]

[ X, X, X ]   --->   [ **, 2*, 43 ]

And in this case you output a truthy value because you used all the digits from [ 1, 3, 3 ].

The numbers [ 903, 1661, 3055 ] are also generated by [ 1, 3, 3 ], but the output for them is a falsy value:

[ 1, 3, 3 ]   --->   [ 903, 1661, 3055 ]
               ||
              _||_
              \  /
               \/
[ X, 3, 3 ]   --->   [ 903, *661, 3055 ]

[ X, X, 3 ]   --->   [ 903, *661, *055 ]

[ X, X, 3 ]   --->   [ 903, *661, *055 ] can't find any 3 after the last blanked digit

Input

Three integers. (One by one, into an array, as one or more a strings, split like bananas, etc.)
You can even take them in descending order if like.

Output

Choose a truthy and a falsy value and be consistent with them.

Standard rules apply for your answer, with standard I/O conventions, while default Loopholes are forbidden.

It would be nice if you could provide an easy way to try your program and possibly an explanation of how it works.

This is code-golf, the shortest wins.

Test cases

Soon...

Meta

• Any feedback / suggestion?
• I thought about considering the digits of x,y,z as always, but blanking out their occurrence in a,b,c from right-to-left, so that who participated to the previous lobster challenges would have to renew this part of the answer. Do you think it would be a good thing?

Answer 24

Challenge

Print all the Tamil characters in any order you like. They should be 12 vowels, 18 consonants and the special symbol ஃ .

Your code should not print anything except for those letters but it can print one letter per line.

The consonants are: க் ங் ச் ஞ் ட் ண் த் ந் ப் ம் ய் ர் ல் வ் ழ் ள் ற் ன்

The vowels are: அ ஆ இ ஈ உ ஊ எ ஏ ஐ ஒ ஓ ஔ

Shortest code wins

Answer 25

Generate a "Pi-ey" number

mathpifastest-codecode-golf

Generate the smallest integer of the form \$x^x\$ with \$10^{n-1}\cdotπ\$ digits, rounded down, given \$n\$. If there is no such number, take the nearest number that has as many digits of \$π\$ in its digit count. For example, if \$n=5\$, then the number of digits would be 31415. If there was no such number of form \$x^x\$, then take the nearest digit count similar to 31415, like 31414 and 31416.

If there are multiple values of \$x\$ that will work, whichever one is closer to \$3.1415926e3141...\$ will be the chosen value. For instance, if two solutions for \$n=5\$ were \$1.234e31414\$ and \$1.234e31416\$, we would select the former, as it is closer to \$3.1415926...e31415\$.

Test cases:

Rules:

• Shortest amount of bytes of code wins
• Please post the number of bytes as well as the runtime for \$n=5\$.
• It is recommended that you post your score (below), but is not required.

Scoring

• Your score will be based on your program time and length. \$\text{score} = \text{program length in bytes} + 10 \times \text{time to execute in seconds}\$

Answer 26

Compute the analysis spectrum

This is based on a task I had in work a few years back.

A diode-array detector (DAD) is a kind of chromatography detector which fires light into a sample and detects the strength of the light that passes through it at different wavelengths. From this you can determine, among other things, the contents or the purity of the sample.

Most detectors can only detect on one wavelength. A DAD however can scan across a spectrum of wavelengths, typically from 190nm to 650nm. From that spectrum we can then pick out the wavelengths that we're interested in. Maybe for our sample we want to analyse it at wavelengths 300nm, 350nm, and 550nm. These are called 'channels'.

Each wavelength may also have a bandwidth across which the signal strength is averaged. If we have analyse on wavelength 420nm, with a bandwidth of 10nm, the range for that channel would be from 415nm to 425nm (5nm lower, 5nm higher than the base wavelength). However, this bandwidth is optional.

The DAD we'll be working with does not take a set of channels, but rather we must provide it with a minimum wavelength and a maximum wavelength to detect across. This will be our task.

The Challenge

Write a program or function that, when given a collection of channels, determines the lowest and highest wavelength to analyse across for these channels.

For this challenge, a channel consists of an integer wavelength, and an optional integer bandwidth. The wavelength can be positive or negative, but the bandwidth is always positive.

Bandwidths can be odd numbers, but in that case you would then shrink it down to an even number.

The upper limit can be the same as the lower limit, but can never be smaller.

Also, you can safely assume that at least one channel is given to your code.

Example 1

Channel 1
Wavelength = 420
Bandwidth = 10

For channel 1, the base wavelength is 420 and the bandwidth is 10.

Channel 1's lower range is the base wavelength minus half of the bandwidth. In this case, it's 420 - (10 / 2) = 415. The upper range is the base wavelength plus half of the bandwidth: 420 + (10 / 2) = 425.

Answers: Lower = 415, upper = 425

Example 2

Channel 1
Wavelength = 394
Bandwidth = 19

Channel 2
Wavelength = 500
Bandwidth = N/A

For channel 1, the base wavelength is 394 and the bandwidth is 19. Because the bandwidth is an odd number, and our DAD cannot accept floating-point numbers, we can round it down to 18.

Channel 1's lower range is the base wavelength minus half of the bandwidth. In this case, it's 394 - (18 / 2) = 385. The upper range is the base wavelength plus half of the bandwidth: 394 + (18 / 2) = 403.

Channel 2 has no bandwidth, so it's range is just at its base wavelength: 500.

Comparing the channel ranges, channel 1 has the minimum lower limit with 385. Channel 2 has the maximum upper limit, with 500.

Answers: Lower = 385, upper = 500

Test cases

Test case 1:

Wavelength 1 = 400
Bandwidth 1 = N/A

Answers: lower = 400, upper = 400

-------------------------------------

Test case 2:

Wavelength 1 = 200
Bandwidth 1 = 15

Answers: lower = 193, upper = 207

-------------------------------------

Test case 3:

Wavelength 1 = 394
Bandwidth 1 = 19

Wavelength 2 = 500
Bandwidth 2 = N/A

Answers: lower = 385, upper = 500

-------------------------------------

Test case 4:

Wavelength 1 = 394
Bandwidth 1 = 40

Wavelength 2 = 500
Bandwidth 2 = 10

Wavelength 3 = 380
Bandwidth 3 = 5

Answers: lower = 374, upper = 505

Rules

The range that you must produce must consist of an integer lower limit and an integer upper limit. This particular DAD cannot accept decimal numbers, so while your code may accept and output floating-point types, the values themselves must be whole numbers.

Computing this range is important for other settings on the DAD. Therefore, you may not take just any input and return an extremely small lower limit and/or an extremely large upper limit. Your outputs must be based on your inputs.

Standard rules apply, including the default I/O rules. Similarly, default loopholes are forbidden.

Finally, this is code-golf so shortest answer in bytes wins.

Sandbox Questions

• Is the challenge itself too complex or too easy?
• Is the requirement for whole-numbered outputs valid, or does it seem a little bit arbitrary?
• Are the examples and the test cases useful?
• Finally, would this be an interesting challenge?

Answer 27

Print the nth sequence from oeis

The input is one natural number n - the sequence number

Your task is to put this numeric link https://oeis.org/A (example of a link with n = 1: https://oeis.org/A1), then you should get the html of this page and get the sequence from there

Examples:

n -> sequence
1 -> 0, 1, 1, 1, 2, 1, 2, 1, 5, 2, 2, 1, 5, 1, 2, 1, 14, 1, 5, 1, 5, 2, 2, 1, 15, 2, 2, 5, 4, 1, 4, 1, 51, 1, 2, 1, 14, 1, 2, 2, 14, 1, 6, 1, 4, 2, 2, 1, 52, 2, 5, 1, 5, 1, 15, 2, 13, 2, 2, 1, 13, 1, 2, 4, 267, 1, 4, 1, 5, 1, 4, 1, 50, 1, 2, 3, 4, 1, 6, 1, 52, 15, 2, 1, 15, 1, 2, 1, 12, 1, 10, 1, 4, 2
2 -> 1, 2, 2, 1, 1, 2, 1, 2, 2, 1, 2, 2, 1, 1, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 1, 2, 2, 1, 1, 2, 1, 1, 2, 1, 2, 2, 1, 2, 2, 1, 1, 2, 1, 2, 2, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 2, 2, 1, 1, 2, 1, 2, 2, 1, 2, 2, 1, 1, 2, 1, 1, 2, 1, 2, 2, 1, 2, 1, 1, 2, 2, 1, 2, 2, 1, 1, 2, 1, 2, 2, 1, 2, 2, 1, 1, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 1, 2, 2
3 -> 1, 1, 1, 1, 2, 2, 1, 2, 2, 2, 3, 2, 2, 4, 2, 2, 4, 2, 3, 4, 4, 2, 3, 4, 2, 6, 3, 2, 6, 4, 3, 4, 4, 4, 6, 4, 2, 6, 4, 4, 8, 4, 3, 6, 4, 4, 5, 4, 4, 6, 6, 4, 6, 6, 4, 8, 4, 2, 9, 4, 6, 8, 4, 4, 8, 8, 3, 8, 8, 4, 7, 4, 4, 10, 6, 6, 8, 4, 5, 8, 6, 4, 9, 8, 4, 10, 6, 4, 12, 8, 6, 6, 4, 8, 8, 8, 4, 8, 6, 4
4 -> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
5 -> 1, 2, 2, 3, 2, 4, 2, 4, 3, 4, 2, 6, 2, 4, 4, 5, 2, 6, 2, 6, 4, 4, 2, 8, 3, 4, 4, 6, 2, 8, 2, 6, 4, 4, 4, 9, 2, 4, 4, 8, 2, 8, 2, 6, 6, 4, 2, 10, 3, 6, 4, 6, 2, 8, 4, 8, 4, 4, 2, 12, 2, 4, 6, 7, 4, 8, 2, 6, 4, 8, 2, 12, 2, 4, 6, 6, 4, 8, 2, 10, 5, 4, 2, 12, 4, 4, 4, 8, 2, 12, 4, 6, 4, 4, 4, 12, 2, 6, 6, 9, 2, 8, 2, 8
6 -> 1, 1, 2, 2, 3, 3, 4, 4, 4, 5, 5, 6, 6, 6, 6, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 10, 10, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18
7 -> 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
8 -> 1, 1, 2, 2, 3, 4, 5, 6, 7, 8, 11, 12, 15, 16, 19, 22, 25, 28, 31, 34, 40, 43, 49, 52, 58, 64, 70, 76, 82, 88, 98, 104, 114, 120, 130, 140, 150, 160, 170, 180, 195, 205, 220, 230, 245, 260, 275, 290, 305, 320, 341, 356, 377, 392, 413, 434, 455, 476, 497, 518, 546
9 -> 1, 1, 1, 2, 2, 3, 4, 5, 6, 8, 10, 12, 15, 18, 22, 27, 32, 38, 46, 54, 64, 76, 89, 104, 122, 142, 165, 192, 222, 256, 296, 340, 390, 448, 512, 585, 668, 760, 864, 982, 1113, 1260, 1426, 1610, 1816, 2048, 2304, 2590, 2910, 3264, 3658, 4097, 4582, 5120, 5718, 6378

code-golf, internet

Answer 28

Posted

Answer 29

post

Answer 30

Introduction

Book cipher

A Book cipher is a very unique method of a encipher. Here's how's it done:

• You have a book / a document or a article (something full of text, the more pages of text the better).
• You have a message to convey (a secret, of some sort)
• You simply-put read trough the text and the secret message (may come from input, or reading it from 2 separate files) - split it into words (so, separate spaces, commas and [dots]) so, ',' , '.' and spaces is the only requirement, how is not really that hugely important and you keep the count of how many words there are in the text, now input the secret message (note, the secret's words must be in the text, so if you secret was "My Secret" then, the words "My" and "Secrets" must both exist in the text.) and output the position of the inputted secret message. (E.g if the word "My" was nearly at the first page, maybe the 20th Word in the text, the program should print out '20'. Same with the word "Secrets", if that maybe were later, (let say the 93th word in the text) then your program should print out '93'.

Note the data type of input and output:

output numbers: Integers.

Input numbers: Integers

( Excluding if the secret actually contains a number, then it does not need to be treated as a int. Can be a plus if it does but is not necessary.)

Mini Example:

document.txt - file that contains text.

Secret: "My Secret"

(in the text, this is the 20th and the 93th word) (Note, this is only a made up secret, it is not from a real file, or a real input) a more better example is below.

Program input:

You enter "My Secret"

Program output:

20

93

And, again - you enter those numbers(**Integers**):

20 93

Program outputs:

My

Secret

this is just to show how input and outputs are related to each other.

For reference (if needed) You have a Python3 implementation available at my GitHub page, to see a book cipher in action here: GitHub - Book cipher in Py3

• Why is this challenge interesting?

I personally think this is a educational (and interesting) challenge ( one might also exercise, because of how simple it might seem to make, but really took myself - literally years to even know how to implement this correctly)

Interesting article to get some background of what Cicada3301 is (not my site) - https://www.clevcode.org/cicada-3301/

Wikipedia: Cicada3301

I created this challenge both to, see other peoples methods of solving this (you are free to use any programming language!) and also - how long it would take others (For me, really I think it took more than 4 years actually - even in Python3. It looks simple but, for me - really not)

• A motivating fact: There are still so little info (especially on example codes) on the internet(at least by the time writing this challenge) about just, book cipher implementations

Challenge

I would highly suggest making dedicated functions for this challenge

• (instead of writing all code in the main() function - but it's totally fine to have it all in main!)

Operation:

Here's how the program should read, process, and output the result:

First, take the text (the book/document, with the lots of text, (not the secret)) and:

Note: The text can either be entered or read from a file. You choose this.

1. read it (From a file, or enter it as input)
2. split it into words (by, I.e detecting '.', spaces(' '), and commas ',') (Or if you already have split the input & are ready to move on to step 3, do that :) )
3. count the number of words.

Repeat this process with the Secret input part.

So, the input secret part should be:

• read it (from, again a file or enter it as input)
• split it (i.e if your input was "My Secret" - split it into words like so: "My" "Secret")

My Python3 implementation only separate spaces.

The Key sequence - this is the nth words your text contains, e.g the 93th word in above example "Secrets".

The winner will be chosen by how short the code is. (So, the shortest code = win)

Example Input and Output

example file used 'document1.txt'in this section is available at the GitHub page. as well as the Python3 file used in the example below.

The output of your program should match the output of the Python3 program.

Input:

python3 bookcipher.py

input text: a house with a Bob inside

Output:

you entered these words: ['a', 'house', 'with', 'a', 'Bob', 'inside']

2

3

5

2

0

30

Input again: (decrypting)

input key-sequence sep. With spaces: 2 3 5 2 0 30

a

house

with

a

Bob

inside