# All Questions

10,438 questions
92 views

### Calculating total slots

Given a list of jobs, which must be done in order, with each taking a slot to do, how long will it take to perform them all if after doing a job the same job cannot be done for the next two slots (...
4k views

### Make a Bowl of Alphabet Soup

This is what we'll call a bowl of alphabet soup - a roughly circular ascii-art shape with the 26 uppercase English letters (A-Z) arranged clockwise to form the perimeter: ...
172 views

### Japanese Multiplication [duplicate]

There's a visual method for multiplication that is taught to Japanese schoolchildren [citation needed] that uses lines and crossings to get the answer. Image Source Your task is to implement this in ...
1k views

### Multiplicative persistence

Multiplicative Persistence Multiply all the digits in a number Repeat until you have a single digit left As explained by Numberphile: Numberphile "What's special about 277777788888899?" Numberphile ...
39 views

### Nearest hamming cycle period in MD5

This riddle was inspired by that thread. Consider that you are super-hacker and try to break MD5 hashing algorithm by looking for a hash collisions for a given hash string which your friend gave to ...
35k views

### 1, 2, Fizz, 4, Buzz

Introduction In our recent effort to collect catalogues of shortest solutions for standard programming exercises, here is PPCG's first ever vanilla FizzBuzz challenge. If you wish to see other ...
10k views

### Count of “a”s and “b”s must be equal. Did you get it computer?

In the popular (and essential) computer science book, An Introduction to Formal Languages and Automata by Peter Linz, the following formal language is frequently stated: mainly because this language ...
4k views

### StringgnirtSStringgnirtSStringgnirtS

Here is a relatively simple challenge for you. Given a string of length N, output the string forwards, then backwards, then forwards, then backwards... etc. N times. For example, if your input was <...
2k views

### Count repetitions of an array

You will receive an array and must return the number of integers that occur more than once. [234, 2, 12, 234, 5, 10, 1000, 2, 99, 234] This will return 2, since ...
3k views

### Code Golf: 6174 - Kaprekar's mythical constant

Why is the number 6174 so interesting? As defined by Wikipedia Take any four-digit number, using at least two different digits. (Leading zeros are allowed.) Arrange the digits in ascending ...
28 views

### Masm 615 Assembly language question [on hold]

need help with an assembly program which does the following: using Masm 615 assemble languahe define an array of 32-bit integers (i.e. DWORDS) .data sarray DWORD 500h, 400h, 300h, 200h, ...
10k views

### Make an error quine!

Your challenge: write a "program", for a language of your choice, that causes the compiler/interpreter/runtime to produce error output when compiling/running your program which is identical to your ...
15k views

### “99 Bottles of Beer”

Write a program that outputs the lyrics to 99 Bottles of Beer, in as few bytes as possible. Lyrics: ...
823 views

### Visual Long Multiplication

There is a nice way to perform long multiplication for two integers without having to do anything but counting, which occasional gets shared around the internet. You write the digits of each number as ...
14k views

### Sing Baby Shark

"Baby Shark" is a children's song about a family of sharks. Having long been popular as a campfire song, it has been popularized since the mid-2000s by social media, online video and radio. - ...
2k views

### Draw the Hilbert Curve

A Hilbert Curve is a type of space-filling curve, and it basically maps a line to a plane. Each point in the line corresponds to just one point in the plane, and each point in the plane corresponds to ...
30k views

### Without using numbers, get the highest salary you can. But don't exaggerate!

As I'm applying for some jobs whose job advert doesn't state the salary, I imagined a particularly evil interviewer that would give the candidate the possibility to decide their own salary ...by "...
116k views

### “Hello, World!”

So... uh... this is a bit embarrassing. But we don't have a plain "Hello, World!" challenge yet (despite having 35 variants tagged with hello-world, and counting). While this is not the most ...
1k views

### The Digit Triangles

Challenge: Input: A positive integer $n$ Output: Create a list in the range $[1,n]$, and join it together to a string (i.e. $n=13$ would be the string ...
434 views

### New Order #1: How does this feel?

Introduction Putting all positive numbers in its regular order (1, 2, 3, ...) is a bit boring, isn't it? So here is a series of challenges around permutations (reshuffelings) of all positive numbers. ...
677 views

### New Order #2: Turn My Way

Introduction (may be ignored) Putting all positive numbers in its regular order (1, 2, 3, ...) is a bit boring, isn't it? So here is a series of challenges around permutations (reshuffelings) of all ...
15k views

### Shortest code to produce non-deterministic output

You need to produce output that is non-deterministic. In this case, this will be defined to mean that the output will not always be the same result. Rules: A pseudo-random number generator that ...
4k views

### Tips for golfing in PowerShell

What general tips do you have for golfing in Windows PowerShell? I'm looking for ideas that can be applied to code golf problems in general that are at least somewhat specific to PowerShell (e.g. "...
2k views

### Reverse a string by chunks

Your task is to write a program which, given a number and a string, splits the string into chunks of that size and reverses them. Rules Your program will receive a positive integer ...
1k views

### The Base in the mix

Input: A list/array of integers for which each item is in the range of 2-36. Output: The sum of the integers (as base 10), where each next integer is in the base ...
2k views

### Chessboard pattern

Input: a positive number, smaller then 80, from stdin or as a command-line argument. Output: A square chessboard pattern, the size of the input number. The dark fields are represented by the letter '...
3k views

### Print the f × f times table

4k views

It is very hard to remember my password, so I came up with a way to generate a password. The way I generate my password is from a word or a sentence, following these steps: Start from left to right ...
1k views

### Terms of the EKG sequence

Introduction The EKG sequence begins with 1 and 2, then the rule is that the next term is the smallest positive integer not already in the sequence and whose common factor with the last term is ...
5k views

### Tips for golfing in 05AB1E

Do you have any tips for code-golfing in 05AB1E, a golfing language created by Adnan? Your tips should be at least somewhat specific to 05AB1E. Please post one tip per answer.
1k views

### Output visual diagram of picture

Write a program that inputs the dimensions of a painting, the matting width, and the frame width for a framed portrait. The program should output a diagram using the symbol ...
2k views

### Convert number to a base where its representation has most “4”s

Inspired by this. There is a number, given as either integer, string or array of digits (your choice). Find the base in which the representation of the number will have most "4"s and return that base. ...
15k views

### Eww, those bytes are gross

Write a program or function that, when given a string, filters out as many distinct bytes as it can and returns the cleaned string. However, since your program hates them, none of these bytes can be ...
21k views

### It took me a lot of time to make this, pls like. (YouTube Comments #1)

Hold up..... this isn't trolling. Background These days on YouTube, comment sections are littered with such patterns: ...
14k views

### Create output twice the length of the code

The Challenge Write a complete program that writes twice as many bytes to standard output as the length of the program. Rules The program must write ASCII characters to the standard output. The ...
434 views

### Gotta Collect 'Em All

Your task here will be to write a very dumb AI capable of fetching all treasures on a map. Map The map is defined as follow: (artist-mode™-powered) Basic case: <...
3k views

### Deal the cards to the players

Tonight is card game night! You are the dealer and your task is to write a program to deal the cards to the players. Given an array of cards and the number of players, you need to split the array of ...
2k views

### 8bit virtual machine

Background I like my old 8-bit 6502 chip. It's even fun to solve some of the challenges here on PPCG in 6502 machine code. But some things that should be simple (like, read in data or output to ...
99 views

### What color is your web page? EDITTED [on hold]

A business owner wants to create a website home page, whose background color dynamically and linearly changes with the time of the day based upon the following: Midnight: Black Between Midnight and ...
226 views

### Convert ASCII art numbers to integers

Inspired by this game Challenge: Given an ASCII art string representing a number, output that number. Example: ...
4k views

### I'm too cold, turn up the temperature

This is my first golf contest. What you need to do Build me, in the shortest amount of bytes possible, my AC remote control system. My room is too cold right now, and I'm missing my remote. Now, I ...
6k views

### Would this string work as string?

Write a program that takes a single line string that you can assume will only contain the characters /\_‾. (That's forward and backward slash, underline and ...
6k views

### N-dimensional N^N array filled with N

In: Enough memory and a positive integer N Out: N-dimensional N^N array filled with N, where N^N means N terms of N-by-N-by-N-by... Examples: 1: [1] ...
2k views

### Is this Pascal's Matrix?

In Pascal's triangle each number is the sum of the two numbers directly above it, treating empty spots as zero: By rotating the triangle, we can cut out square matrices of varying sizes and rotations ...
4k views

### Is it a pangram?

Write a function or program that takes as its input a string and prints a truthy value if the string is a pangram (a sequence of letters containing at least one of each letter in the English alphabet) ...
4k views

### Print the amount of ones in a binary number without using bitwise operators

Description Given a number, print the amount of 1s it has in binary representation. Input A number >= 0 in base 10 that ...
449 views

### Offset in split text content

You will be given an ASCII text. This text may have zero, one or many appearances of a split a character (let's assume it will be the space character ) You will ...
5k views

### It's a yearly task, alright

Given a number 1≤n≤365, output the nth day of the year in "Day-numberth Month" format. For example, given 1, you should output "1st January", without "of". The Gregorian calendar will be used and the ...