All Questions

14
votes
4answers
359 views

Dig a border trench

Background: Too many illegal immigrants from Blandia are crossing the border to Astan. The emperor of Astan has tasked you with digging a trench to keep them out, and Blandia must pay for the expenses....
15
votes
23answers
383 views

Equal, sum or difference!

Write shortest possible code that will return true if the two given integer values are equal or their sum or difference is 5. Example test cases: ...
0
votes
2answers
76 views

Work out \$x^y\$ using only addition and subtraction [duplicate]

The challenge is to implement a function or program that takes two numbers, \$x\$ and \$y\$ and return the result of \$x^y\$. The program cannot use any other mathematical operation other than \$+\$ ...
0
votes
0answers
68 views

One way road algorithm [on hold]

In a certain region all places are the one by road. But one-way traffic for all roads; if you are allowed to go from A to B via the direct route, you can not along that road from B to A. If you want ...
1
vote
0answers
71 views

Chess move validation [duplicate]

Write a program that accepts chess moves, validate them and shows the results. The program should: Check wheter or not a move is valid Check if a king is in check or in checkmate Process the changes ...
24
votes
15answers
3k views

Matrix Jigsaw Puzzles

Input: An integer n Two equal-sized square matrices (with their width/height being a multiple of n) Output: One of two ...
8
votes
21answers
1k views

Unix timestamp to datetime string

Given a unix timestamp as an input, give a datetime string, in a format like so: "YYMMDD.HHmm" Rules The input is a number (integer) of a millisecond-precise UNIX epoch time (milliseconds since 1970 ...
-2
votes
0answers
69 views

Givean a Tetris matrix, list all pieces [closed]

Say you have a simple tetris "game". Each piece have 1 single colour, and you read moves as: *Type *Rotation *Column of the first left piece's square inside matrix. Pieces fall till the end or ...
9
votes
14answers
282 views

Matrix Jigsaw Puzzle Pieces

(Randomly inspired by https://codegolf.meta.stackexchange.com/a/17272/42963) Given a rectangular matrix of digits (i.e., 0 - 9), output the "pieces" of the matrix ...
0
votes
0answers
87 views

Custom check digit algorithm [closed]

Your challenge is to create a simple Check-Digit algorithm. Inputs: Dictionary - set of unique characters, for example "ABCDEF") Length - integer Input digit - this is what we are calculating the ...
14
votes
2answers
443 views
+100

Number of \$n\$-carbon alkanes

Given a positive number \$n\$, find the number of alkanes with \$n\$ carbon atoms, ignoring stereoisomers; or equivalently, the number of unlabeled trees with \$n\$ nodes, such that every node has ...
0
votes
0answers
105 views

Find is string is magic or not [closed]

A string is a magic string if It consists of only digits Is a concatenation of 8 unique integers between 1 and 80 Challenge Write code which, given a string as input, outputs all the lists of ...
0
votes
0answers
71 views

Add to number using regex [closed]

Using a regular expression, I want to add 1 to 1 to get 2, 1 to 2 to get 3, 1 to 3 to get 4, 1 to 22 to get 23, 1 to 145 to get 146, etc. So I would have the expression, the value, the replacement, ...
30
votes
12answers
4k views

What are the repeating Fibonacci Digits?

As you probably know, a Fibonacci Number is one which is the sum of the previous two numbers in the series. A Fibonacci Digit™ is one which is the sum of the two previous digits. For instance, for ...
-3
votes
0answers
77 views

Split Longer Message to multiple short messages [duplicate]

Post short messages limited to 50 Example "I can't believe Tweeter now supports chunking my messages, so I don't have to do it myself." This is 91 ...
4
votes
6answers
221 views

Nested lists as printable 2D objects [on hold]

I don't know if something like this exists already (and I'm not finding the right key words) but if not, it felt like it could be an interesting coding puzzle. The challenge is, to take an ...
6
votes
3answers
271 views

Range interval insert which should split into unique ranges

Given a range and a list thereof, while keeping the existing intervals in the list unchanged, split the additional range into sub-intervals and add them to the list, such that all the ranges in the ...
-1
votes
0answers
41 views

Matlab Question - How to optimize parameters for two data sets [closed]

This is rather an easy problem but I cannot get my head around. I have two curves in the form, say F(xi,fi) and G(xi,gi), with i = 1 to 65. F and G are supposed to be the same, but I get them ...
5
votes
12answers
421 views

An Séimhiú agus an tUrú

An Séimhiú agus an tUrú In Irish Gaelic (Gaeilge) there are a number of ways that the start of a word can be changed. The most common of these are lenition (an séimhiú) and eclipsis (an t-urú) ...
24
votes
38answers
2k views

Enumerate each series of identical numbers in-place

Given a list of strictly positive integers, go through each distinct number and replace all occurrences of it with successive indices (zero or one based) of a new series. Examples ...
6
votes
11answers
374 views

Mis-decode a date

Background Inspired by a now deleted question by John Burger from which I quote: Now obviously no human made this mistake. It's a mis-decode of something - perhaps the ISBN? My question is: ...
10
votes
15answers
2k views

Multi-level marketing “legs” investment rule

Multi-level marketing related challenge. A peer wants to get rewarded. So it attracted N investors (N>=1), each i-th ...
5
votes
0answers
116 views

Pattern Finder - Find Repeated Pattern in String [closed]

Introduction This is a little challenge with the goal of identifying repeated pattern "blocks" in a string, and outputting them with their frequency of occurence from left to right. A friend asked ...
13
votes
13answers
482 views

Write a function/method that takes in a string and spells that word out using the NATO Phonetic Alphabet. Titlecase optional

Write a program that takes in a string and spells that word out using the NATO Phonetic Alphabet. The mapping is as follows: ...
17
votes
16answers
1k views

How many consecutive descending numbers in my number?

2019 has come and probably everyone has noticed the peculiarity of this number: it's in fact composed by two sub-numbers (20 and 19) representing a sequence of consecutive descending numbers. ...
5
votes
2answers
226 views

Execute Triangularity Move

TL;DR for those not interested: Look at the test cases at the bottom. Have a program/function that outputs the 2D list displayed for the given input. Introduction: On November 15th, 2018 puzzle ...
12
votes
14answers
1k views

Clock (transliterate) Cipher

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 ...
57
votes
42answers
10k views

Oreoorererereoo

Oreoorererereoo Given an input string that is similar to the word "oreo", give an ASCII representation of the cookie that is as wide as the input string (to ensure cookie stability). Rules The ...
5
votes
1answer
261 views

Surreal Numbers

Surreal Numbers Surreal numbers are one way of describing numbers using sets. In this challenge you will determine the value of a surreal number. Intro A surreal number consists of two sets: a left ...
0
votes
1answer
75 views

Remove indentation [duplicate]

Write a program which removes any common leading spaces from the input string. For example, if the least indented line started with 3 spaces, and every other line has ...
8
votes
7answers
791 views

Length of the Longest Descent

Your task is to determine the length of the longest descent down a "mountain" represented as a grid of integer heights. A "descent" is any path from a starting cell to orthogonally adjacent cells with ...
13
votes
20answers
1k views

Find if a list is an ABC-triple

Three positive integers A, B, C are ABC-triple if they are coprime, with A < B and satisfying the relation : A + B = C Examples : 1, 8, 9 is an ABC-triple ...
3
votes
0answers
139 views

Min-Max GHC command line error bytes to bytes of source code

GHC command line errors can be horrible, lets make them as bad as possible. To disincentivize very long programs use the following formula to calculate your "score". ...
9
votes
0answers
96 views

Order of Elements of the Rubik's Cube [duplicate]

Introduction All the possible moves and their combinations of a Rubik's Cube form a group. A group in general is a set with some binary operation defined on it. It must contain a neutral element with ...
0
votes
0answers
45 views

Polynomial to String [duplicate]

I'm new to code-golf, but I was trying to solve this problem myself, and thought there must be a much "better"/shorter way of doing it. Given a sequence (list) of numbers \$a_0, a_1,\cdots,a_n\$, ...
21
votes
18answers
2k views

Collapsing numbers

Let's define the a function on natural numbers \$n\$, written as base 10 digits \$d_k\; d_{k-1}\; \dotsc\; d_1\; d_0\$, as follows: As long as there are equal adjacent digits \$d_i\;d_{i-1}\$, ...
17
votes
16answers
1k views

Get the date of the nth day of week in a given year and month

Introduction Often, people refer to dates as the "second Friday in August, 2018" or the "fourth Sunday in March, 2012". But it's hard to tell what date that is! Your task to is to write a program ...
16
votes
18answers
735 views

Most contributing rows

Given a non-empty matrix of non-negative integers, answer which unique rows contribute most to the sum total of elements in the matrix. Answer by any reasonable indication, for example a mask of the ...
12
votes
13answers
421 views

Count the contiguous submatrices

Migrated from chat Given two non-empty non-negative integer matrices A and B, answer the number of times A occurs as a contiguous, possibly overlapping, submatrix in B. Examples/Rules 0. There may ...
2
votes
3answers
96 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 ...
6
votes
5answers
184 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: ...
4
votes
6answers
399 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 ...
21
votes
12answers
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 ...
49
votes
30answers
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 ...
1
vote
1answer
204 views

Pumping quine radix

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\$ ...
39
votes
4answers
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, ...
4
votes
7answers
354 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: ...
25
votes
11answers
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 ...
14
votes
22answers
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 ...
20
votes
20answers
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, ...

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