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Challenges

Code challenges of all types. For questions about golfing, bowling, etc, use Q&A. For questions about this community, use Meta. To get feedback on a challenge before posting it, use Sandbox.

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66%
+2 −0
Expected value of highest dice rolled

You roll $N$ six-sided dice simultaneously. Your score is the highest number rolled. If you play this game many times, what is the expected value (mean) of your score? Input A positive integer ...

2 answers  ·  posted 3mo ago by trichoplax‭  ·  last activity 3mo ago by RubenVerg‭

60%
+1 −0
Reverse engineer the colors for a layout.

At my job we have to sometimes lay out materials. Materials come in large long rolls and are cut into smaller pieces when being laid out. When we order the rolls we draw up a layout document which...

0 answers  ·  posted 2mo ago by WheatWizard‭

66%
+2 −0
Are these reduced forms of the same thing?

Task You are going to take three strings as input $A$, $B$ and $X$. And your goal is to determine if there exists a third string $S$ such that both $A$ and $B$ can be formed by iteratively removin...

0 answers  ·  posted 3mo ago by WheatWizard‭  ·  edited 3mo ago by WheatWizard‭

77%
+5 −0
Decoding a non injective bit matrix encoding

The problem Someone has created an encoding format for square bit matrices, however they have found it isn't perfect! One encoding may not decode to exactly one matrix, or it may not even be possi...

0 answers  ·  posted 7mo ago by Aftermost2167‭  ·  edited 7mo ago by Aftermost2167‭

71%
+3 −0
Label a hinged tetromino

Given a hinged tetromino, give it a unique, consistent label independent of location, rotation, and reflection. Tetrominoes A tetromino is a connected subset of the square tiling, composed of 4 s...

2 answers  ·  posted 3mo ago by trichoplax‭  ·  last activity 2mo ago by RubenVerg‭

22%
+0 −5
HOW TO HANDLE THIS ERROR: "Failed to get input map for signature: serving_default" [closed]

import requests import json import numpy as np import base64 import cv2 Replace this with the actual image path you want to test image_path = 'H_L_.jpg' Read and preprocess the image image ...

0 answers  ·  posted 2mo ago by mjkatre18‭  ·  closed 2mo ago by Mithical‭

66%
+2 −0
Build a replacement ball in regex.

In this challenge you will take a number $n$ and a string $X$ of length $\geq n$, and produce a regular expression which matches all strings that are withing $n$ character substitutions of $X$. Sp...

3 answers  ·  posted 3mo ago by WheatWizard‭  ·  last activity 3mo ago by WheatWizard‭

66%
+2 −0
Find near miss prime multiples.

Given a number $n \geq 3$ as input output the smallest number $k$ such that the modular residues of $k$ by the first $n$ primes is exactly $\{-1,0,1\}$. That is there is a prime in the first $n$ p...

0 answers  ·  posted 3mo ago by WheatWizard‭  ·  edited 3mo ago by WheatWizard‭

66%
+2 −0
Prove commutativity on this monoid presentation.

Given two binary strings $A$ and $B$ such that $A$ is an anagram of $B$, output a third binary string $S$ such that both $A$ and $B$ can be created by iterated removals of the substring $10101$ fro...

0 answers  ·  posted 3mo ago by WheatWizard‭

66%
+2 −0
Give the fool's fibonacci sequence

Recently I asked for tips on improving some code-golf of mine. The code was supposed to output every third value of the Fibonacci sequence starting with 2: 2,8,34,144,610,2584,10946,46368,196418,...

0 answers  ·  posted 1mo ago by WheatWizard‭  ·  edited 1mo ago by WheatWizard‭

71%
+3 −0
Sort letters by height

Given a sequence of lower case letters, sort them into order of height. Heights The heights of letters are dependent on font, so for this challenge the height order to be used is as defined below...

5 answers  ·  posted 11mo ago by trichoplax‭  ·  last activity 2mo ago by Taeir‭

66%
+2 −0
Count polyomino bisections

An polyomino is a non-empty connected subset of the square tiling consisting of squares joined along their edges. We will not require that polyominos be simply connected, that is they can have hole...

0 answers  ·  posted 3mo ago by WheatWizard‭

50%
+0 −0
Word suggesting

Suggest a word from a word list, given a string. Motivation Imagine typing a word one letter at a time, and seeing a suggested word after each letter is typed. At first the suggested word is simp...

0 answers  ·  posted 27d ago by trichoplax‭

81%
+7 −0
Efficient censorship

You are a low-level censor working for the Ministry of Media Accuracy. Part of your job is to make sure that certain words don't appear in publications. Every morning you get a fresh stack of next...

4 answers  ·  posted 3mo ago by WheatWizard‭  ·  last activity 3mo ago by Shaggy‭

66%
+2 −0
Is it part of the mandelbrot set?

Input is a number, you have to decide if it is part of the mandelbrot set or not, after at least 16 iterations. This is done by applying this formula: $z_n = z_{n-1}^2 + c$ repeatedly. $c$ is the ...

0 answers  ·  posted 12d ago by [Object object]‭  ·  edited 3d ago by [Object object]‭

66%
+2 −0
Mark my beacons

Given a grid of numbers, mark the concentric areas around nonzero elements (beacons) decreasing from the value of the beacon till 1. For example, here are some grids with a single beacon: Size 1:...

0 answers  ·  posted 1y ago by Razetime‭  ·  last activity 12mo ago by Moshi‭

75%
+4 −0
Probability of rolling all 6 dice faces

The probability of rolling every number from 1 to 6 with $N$ six-sided dice. Input A positive integer $N$. Your code must work for inputs up to and including 10, but may crash, error, or give ...

4 answers  ·  posted 3mo ago by trichoplax‭  ·  last activity 3mo ago by RubenVerg‭

66%
+2 −0
Reverse the bits in a Byte

Simple challenge: Read a byte, swap bit 7 with 0, 6 with 1, 5 with 2 and 4 with 3 and then output the byte. For example the byte 0b1001'1100 would turn into 0b0011'1001. Rules: Shortest code wi...

6 answers  ·  posted 1mo ago by [Object object]‭  ·  last activity 16d ago by lovebuny‭

66%
+2 −0
Determine if a polyomino is "prime"

An $n$-polyomino is a connected subset of the square tiling consisting of $n$ squares. We will not require that polyominos be simply connected, that is they can have holes. We will say a $n$-polyo...

1 answer  ·  posted 3mo ago by WheatWizard‭  ·  edited 3mo ago by WheatWizard‭

66%
+2 −0
Pinwheel ​words

Given a word that can be rotated by 180 degrees (a half turn) about at least one of its 3 axes and continue to be composed of English alphabet letters, output one of its rotated forms. The 3 rotat...

0 answers  ·  posted 11mo ago by trichoplax‭

71%
+3 −0
8 coexisting queens

This is a fixed output challenge. Output a textual representation of a chessboard hosting 8 queens, none of which are attacking each other. There are 92 ways of arranging them, 12 if rotations and...

5 answers  ·  posted 12mo ago by trichoplax‭  ·  last activity 7mo ago by m90‭

66%
+2 −0
Connect the corners without 4 in a row

Connect opposite corners of a rectangle of characters without putting 4 characters in a row. Input Two numbers, W and H, representing the width and height of the rectangle Each number will be ...

1 answer  ·  posted 11mo ago by trichoplax‭  ·  last activity 3mo ago by WheatWizard‭

75%
+4 −0
Knight safe squares

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight. Input An 8 by 8 grid where each square is either a knight or empty T...

3 answers  ·  posted 12mo ago by trichoplax‭  ·  last activity 19d ago by Karl Knechtel‭

81%
+7 −0
Find n Niven Numbers

Challenge A Niven number is a positive integer which is divisible by the sum of its digits. For example, 81 -> 8+1=9 -> 81%9=0. Your task is to find the first n Niven numbers, given n. Te...

7 answers  ·  posted 1y ago by Razetime‭  ·  last activity 1y ago by Shaggy‭

75%
+4 −0
Encode with ROT13.5

Given a string, convert all of its letters using ROT13, and all of its digits using ROT5. This is sometimes referred to as ROT13.5. Input A sequence of printable ASCII characters (character cod...

4 answers  ·  posted 11mo ago by trichoplax‭  ·  last activity 10mo ago by Razetime‭

75%
+4 −0
Calculate the Z-array

Task Given a list of numbers $X$ produce a second list of numbers $Y$ such that $Y_i$ is the length of the longest common prefix of $X$ and $X$ with the first $i$ elements removed. For example if...

1 answer  ·  posted 3mo ago by WheatWizard‭  ·  last activity 3mo ago by TheCodidacter, or rather ACodidacter‭

71%
+3 −0
From the smallest seed

Challenge It's a bootstrapping challenge this time! Write a full program that, once run, writes the source code of another program that in turn, once run, writes the source code for another progra...

2 answers  ·  posted 1y ago by Moshi‭  ·  last activity 1y ago by orthoplex‭

60%
+1 −0
Balanced quinary quasiquine

Given an integer $N$ in balanced quinary, output the first $N$ characters of your source code if $N$ is positive, or the last $-N$ characters of your source code if $N$ is negative. Terminology ...

1 answer  ·  posted 12mo ago by trichoplax‭  ·  edited 11mo ago by trichoplax‭

60%
+1 −0
Chequer checker

A chequer board (also spelt "checker board" in some places) is an 8 by 8 grid of squares alternating between 2 colours. Check whether a provided pattern could be a region of a chequer board. The c...

1 answer  ·  posted 1y ago by trichoplax‭  ·  edited 12mo ago by trichoplax‭

71%
+3 −0
The holeyest base

Given a positive integer as input, indicate which base from 2 to 16 gives the most holes in the representation of the input in that base. The digits used are 0123456789ABCDEF. Note that these incl...

6 answers  ·  posted 12mo ago by trichoplax‭  ·  last activity 12mo ago by Razetime‭

75%
+4 −0
Find the IP address class

Task Given an IP address as a string, find its IP address class. For reference, here is a table: Class Leadingbits Numberof networks Addressesper network Total addressesin class Start...

6 answers  ·  posted 2y ago by Razetime‭  ·  last activity 1y ago by torres‭

80%
+6 −0
Golf golf challenge

The task is to create a program which displays a golf score as text. It takes 2 numbers as input, separated by space or new line: The first number is the par of the specific hole. The second nu...

5 answers  ·  posted 2y ago by Lundin‭  ·  last activity 1y ago by radarek‭

75%
+4 −0
Just the vowels please

Given a sequence of letters, output only the vowels. Input A sequence of letters This may be a string or any ordered data structure of characters (provided it is consistent between inputs) Th...

9 answers  ·  posted 12mo ago by trichoplax‭  ·  last activity 11mo ago by taoh‭

50%
+0 −0
Rationalise recurring binary

Given a potentially recurring binary string, output the number it represents, as a fraction in lowest terms. The notation used in this challenge for recurring digits is non-standard. An r is used ...

0 answers  ·  posted 12mo ago by trichoplax‭  ·  edited 12mo ago by trichoplax‭

86%
+11 −0
Can you give me half?

Challenge idea taken from: Eliseo D'Annunzio Task Provide code that evaluates to 0.5 numerically, i.e. the output must be recognized by your chosen language as a numeric value (Number, float, dou...

23 answers  ·  posted 1y ago by Razetime‭  ·  last activity 2mo ago by RubenVerg‭

50%
+0 −0
Circle of text characters

Given a radius R, output a text representation of a circle. Input A positive integer R (strictly greater than zero) You do not need to handle values of R greater than 32 Output A square ...

0 answers  ·  posted 11mo ago by trichoplax‭  ·  edited 11mo ago by trichoplax‭

66%
+2 −0
Digit antitranspose

Convert a matrix or grid of digits to its antitranspose. For a square matrix , this is its reflection in its antidiagonal. More generally, for a rectangular matrix, this is its reflection in its sk...

4 answers  ·  posted 11mo ago by trichoplax‭  ·  last activity 10mo ago by torres‭

71%
+3 −0
Generalized Sort

Challenge We all know and love the generic sort function, right? However, it only sorts based off one criterion - what if we want more? That's where you come in. Your task is to sort an array bas...

6 answers  ·  posted 2y ago by Moshi‭  ·  last activity 1y ago by radarek‭

75%
+4 −0
The Ludic Numbers

The Ludic Numbers are a sequence that pops up when you apply the sieve of eratosthenes to the natural numbers, completely removing the numbers every iteration. Here is how they are generated: The...

3 answers  ·  posted 2y ago by Razetime‭  ·  last activity 2y ago by General Sebast1an‭

71%
+3 −0
Lowercase, but not just the letters

Given a string of printable ASCII characters, convert them all to lowercase, except not just the letters. ASCII characters that are letters have a bit in their binary representation that is 0 for ...

7 answers  ·  posted 12mo ago by trichoplax‭  ·  edited 2mo ago by trichoplax‭

71%
+3 −0
Multiply two strings

Given two strings, I define their product as follows: If any of the two strings is empty, the product is the empty string. If the second string consists of a single character, the result ...

6 answers  ·  posted 2y ago by celtschk‭  ·  last activity 2y ago by Hakerh400‭

60%
+1 −0
55 fruit salad: choose your own Kolmogorov complexity

This is a fixed output challenge. It is similar to a standard Kolmogorov complexity challenge, except you get to choose your own fixed output. Given no input, output 55 fruits. You may choose any 5...

5 answers  ·  posted 12mo ago by trichoplax‭  ·  last activity 12mo ago by Shaggy‭

71%
+3 −0
My house is destroyed! Can you make me one?

Background A House of I I went on an adventure Grabbed resources and making deeds Like start to work on the materials To build the shelter I need It was a marvelous one At least in the eyes ...

10 answers  ·  posted 2y ago by General Sebast1an‭  ·  last activity 2y ago by Quintec‭

66%
+2 −0
Expand a polynomial

Challenge Given the roots of a polynomial (that is, the $x$ values where the polynomial evaluates to zero), as an array of real numbers, return the polynomial's coefficients. That is, given real ...

4 answers  ·  posted 2y ago by Moshi‭  ·  last activity 2y ago by Moshi‭

75%
+4 −0
Caesar shift cipher

Introduction What is the Caesar shift cipher (ROT$n$)? It's basically a cipher sequence that changes a letter's value from the number chosen. If we use ROT1 on "games", we get "hbnft". The basic i...

7 answers  ·  posted 2y ago by General Sebast1an‭  ·  edited 2y ago by General Sebast1an‭

77%
+5 −0
Create a range grid

This challenge is based on the i. verb from J. A range grid is basically a range of m × n numbers fit into a rectangular grid with m rows and n columns. A 2×3 range grid would be: 0 1 2 3 4 5 ...

8 answers  ·  posted 1y ago by Razetime‭  ·  last activity 1y ago by Shaggy‭

80%
+6 −0
Versatile self-printer

Using your languages of choice, golf a quine - a non-empty program taking no input and only outputting its source. Here, the win condition is your quine working in the most languages. It should be...

1 answer  ·  posted 2y ago by AndrewTheCodegolfer‭  ·  last activity 2y ago by General Sebast1an‭

71%
+3 −0
Convert integer to English

Given a non-negative integer up to $999\,999\,999$, write it in English. The input number can be in any form other than English (though you'll typically want to use the native integer type of your...

3 answers  ·  posted 2y ago by celtschk‭  ·  last activity 2y ago by Moshi‭

71%
+3 −0
Mediocre pop count

Given a sequence of letters, omit those with the highest or lowest pop count. Terminology The pop count or population count of a binary string is the number of 1s in it. For this challenge, the ...

6 answers  ·  posted 12mo ago by trichoplax‭  ·  last activity 9mo ago by A username‭

71%
+3 −0
Three Number Monte

The Rules In this game, each round, every player faces off against every other player in a round robin format. In each match, players pick 3 positive integers that sum to 360. Let's say player 1 p...

2 answers  ·  posted 2y ago by Quintec‭  ·  last activity 2y ago by Moshi‭