All Questions

10,359 questions
112 views

All the digisibles [duplicate]

A natural number (written in the decimal base) is qualified as digisible if and only if it fulfills the following 3 conditions: none of its digits is zero, all the digits that compose it are ...
189 views

Find equally-weighted complete graphs

Graph theory is used to study the relations between objects. A graph is composed of vertices and edges in a diagram such as this: ...
420 views

Corrupting A Binary File By Interpreting It As Text

Using FTP's ASCII mode to transfer binary files is a bad idea. It is likely to corrupt your data. Badly. Let's simulate this corruption! Your task is to write a program which takes a file as input ...
2k views

Eight coins for the fair king

This is a "counterpart" of another puzzle, Eight coins for the fair king on Puzzling.SE. You can read the above puzzle for the background. The details about this puzzle are as follows. A set of 8 ...
5k views

Encode the date in Christmas Eve format

The day this post was published was Christmas Eve. Tomorrow will be Christmas. Yesterday was Christmas Eve Eve. In two days it will be ...
214 views

Inspired (you don't need to know them for this challenge) by the Pumping Lemma for various languages, I propose the following challenge: choose some basis $B \geq 2$ and an integer $n \geq 0$ ...
1k views

Dungeon Crawler

Input A binary matrix $M$ representing the walls of a dungeon. The position $(x,y)$ of the player within the dungeon. The direction $d$ that the player is currently facing (0 = North, 1 = East, ...
370 views

Just Twice Is Nice

Let's have string multiplication to take a string and a positive number and concatenate that string that many times. In Haskell: ...
1k views

Does this Set Represent a Natural Number?

In set theory, the natural numbers $\mathbb{N} = \{0, 1, 2, 3, ...\}$ are usually encoded as pure sets, that is sets which only contain the empty set or other sets that are pure. However, not all ...
2k views

Translate English to Corpus

The Corpus are a fictional faction from the popular video game Warframe who have a somewhat interesting language. Whilst other factions in the game such as the Grineer have some logic behind their ...
1k views

Smallest Diversifying Exponent

A pandigital number is an integer which contains every digit from 0 to 9 at least once. 1234567890, 1902837465000000, and 9023289761326634265 are all pandigital. For the purposes of this challenge, ...
2k views

Parse the Bookworm dictionary format

I've recently been indulging myself in some nostalgia in the form of Bookworm Deluxe: In case you haven't seen it before, it's a word game where the goal is to connect adjacent tiles to form words. ...
240 views

What will be on the top of this decorative calendar?

Someone gave my wife a decorative calendar consisting of four cubes. Here it is showing today's date (as of the posting of this challenge) on the front: When I first saw it, I looked at it from the ...
2k views

Coat of Many Colours

Challenge Given a list of unique colour names as input, sort them in the order that they first appear in Joseph's Amazing Technicolour Dreamcoat. Example ...
254 views

Optimizing swiping across a 1D keyboard

This is a code-challenge with a custom scoring system, where the lowest score wins. Introduction Many smartphones allow to enter text by swiping your finger across the 2D virtual keyboard. This ...
9k views

A game of dice, but avoid number 6

Tournament over! The tournament is now over! The final simulation was run during the night, a total of $3*10^8$ games. The winner is Christian Sievers with his bot OptFor2X. Christian Sievers also ...
2k views

Non-overlapping Matrix Sum

Non-overlapping Matrix Sum Given k arrays of length n, output the maximum sum possible using one element from each array such that no two elements are from the same index. It is guaranteed that k<=...
323 views

Approximate the proportion of integers with neighboring factors

If 1 is not counted as a factor, then 40 has two neighboring factors (4 and 5) 1092 has two neighboring factors (13 and 14) 350 does not have two neighboring factors (out of its factors 2, 5, 7, 10, ...
1k views

Rotation invariant fingerprinting

Imagine we have some polyomino and would like to uniquely identify them, however the polyominos can be rotated, so blindly hashing them won't give us the same fingerprint for a piece and a rotation ...
1k views

Standardize the Samples (Compute the z-Score)

Given a list of floating point numbers, standardize it. Details A list $x_1,x_2,\ldots,x_n$ is standardized if the mean of all values is 0, and the standard deviation is 1. One way to compute this ...
2k views

How many syllables in that number?

I'd love to take a number and know how many syllables are in it, when spoken in English. Let's limit this to positive integers which are less than one thousand. I'm British, so we're going to follow ...
69 views

Sino-Korean numerals [duplicate]

The Korean language has two sets of numerals, a native Korean numerals and Sino-Korean numerals. The native Korean numerals are mostly used for numbers under 100, such as age and time. The Sino-...
2k views

Convert to Suzhou numerals

Suzhou numerals (蘇州碼子; also 花碼) are Chinese decimal numerals: 0 〇 1 〡 一 2 〢 二 3 〣 三 4 〤 5 〥 6 〦 7 〧 8 〨 9 〩 They pretty much work like Arabic numerals, except ...
3k views

How much candy can you eat?

Credit to Geobits in TNB for the idea A post without sufficient detail recently posited an interesting game: 2 children sit in front of an array of candy. Each piece of candy is numbered 1 to ...
412 views

A spiral sequence

Background OEIS sequence A272573 describes a spiral on a hexagonal grid as follows: Start a spiral of numbers on a hexagonal tiling, with the initial hexagon as a(1) = 1. a(n) is the smallest ...
4k views

Draw some expanding arrows

This challenge is about printing a series of growing ASCII-art arrows. I'll describe the pattern in words, but it might be easier to look at what the start of this series looks like: ...
337 views

Hilbertize an image

For a computer vision app I want to do a mapping of an image, in such a way that every pixel fit hilbert curve, instead of conventional layout. So task could be as follows: Task description Given ...
342 views

Print coordinates of an NxN grid [duplicate]

Question: Print out all the coordinates of a NxN grid. Preferably in C, however other languages also accepted Input: N (integer) Output: for N=3, a 3x3 grid: ...
1k views

Iron particles around a magnet

There are some iron particles on a board. We pass a current carrying wire through that board and the particles form circles. Show these circles if input given is the position of the wire. Consider ...
129 views

find the value at kth position when numbers are sorted lexicographically till n [closed]

Ex :- Input: n = 12, k = 5 Output: ans = 2 Sorted list S: ["1", "10", "11", "12", "2", "3", "4", "5", ...., "9"] ans = 2
320 views

Given a positive integer input n seconds, output the time in human readable format. The time will be considered from 00:00:00, 1st January, 1 A.D. Leap years must ...
190 views

Round the digits last digit, over and over

Challenge: Given two inputs, x and y, round x to one less significant figure, then repeat until it has y number of unrounded digits left. (the decimal point does not count as a digit) Input & ...
1k views

Optimal Alphabet Stepping

Given an input string consisting of only letters, return the step-size that results in the minimum amount of steps that are needed to visit all the letters in order over a wrapping alphabet, starting ...
391 views

Code Golf: Letter-Ception

The Challenge: For an input of one letter X (upper or lower case from A to Z) and one digit N (0-9) print the corresponding letter X made of N * X. The letter has to be from this list: ...
1k views

Fill the Bucket

Your task is to fill the bucket with numbers upto a given input. Rules Numbers occupy the leftmost position then rightmost, then leftmost and so on. After overflow, the numbers start to gather ...
104 views

Regex only base64 decoder [closed]

Write a regular expression substitution string which can base64 decode a string using only a regular expression engine built into the language. Eg: ...
1k views

Trifid Cipher (without keyword)

Introduction: I have loads of different ciphers stored in a document I once compiled as a kid, I picked a few of the ones I thought were best suitable for challenges (not too trivial, and not too ...
308 views

Golf Paterson's Worms

Paterson's worms are a kind of cellular automaton that exist on an infinite triangular grid and, every step, they turn in some direction and move one unit. Their defining properties are that they can ...
4k views

Find the number of leading zeroes in a 64-bit integer

Problem: Find the number of leading zeroes in a 64-bit signed integer Rules: The input cannot be treated as string; it can be anything where math and bitwise operations drive the algorithm The ...
2k views

String rotation - output string repeatedly moving first character to the end

The challenge here is to take a string and output all its rotations, by repeatedly moving the first character to the end, once per character in the string, ending with the original string: ...
535 views

Doubled-letter steganography

Steganography hides a given message inside a given carrier, producing a package that does not look suspicious. For this challenge, you will write a program that takes an ASCII message and an ASCII ...
567 views

Satisfying Rounding

Satisfying Rounding You know when you're in science class, and asked to round to 2 sig figs, but your answer is 5.2501...? You should round to ...
54 views

Bracket checking [duplicate]

Consider a string like: a.push(c.push("a",["ad","bd",2,{"ard",duo}]).pop().replace(2,"tg").enc([3,{2,adf},"atr"],5) Write a program that will verify whether a ...
5k views

P Pr Pre Pref Prefi Prefix Prefixe Prefixes

Given some finite list, return a list of all its prefixes, including an empty list, in ascending order of their length. (Basically implementing the Haskell function ...
5k views

Number that can eat itself

Given a positive integer, output a truthy/falsy value as to whether the number can eat itself. Rules Leftmost is the head, rightmost is the tail If the head is greater than or equal to the tail, ...
502 views

Map the cheaters!

After all assignments are submitted, a dictionary is created that maps student number to the hash of their file. This dictionary, or hashmap, or mapping (whatever your language calls it) will look as ...
2k views

Walk Across a Keyboard

Given a word (or any sequence of letters) as input, you must interpolate between each letter such that each adjacent pair of letters in the result is also adjacent on a QWERTY keyboard, as if you ...
142 views

Measuring Mountains [duplicate]

Sum-It is a language I created (quite late) for the Language Design Contest in TNB, for which the theme was "Range". Naturally I interpreted this as "Mountain Range" and created a language about ...