instruction_seed stringlengths 292 48.7k | found_ngrams listlengths 0 21 |
|---|---|
Consider the infinite matrix:
0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
0 0 2 3 0 0 2 3 0 0 2 3 0 0 2 3
0 0 0 4 5 6 0 0 0 4 5 6 0 0 0 4 ...
0 0 0 0 7 8 9 10 0 0 0 0 7 8 9 10
0 0 0 0 0 11 12 13 14 15 0 0 0 0 0 11
...
Each new row of the matrix is co... | [] |
Challenge
Given a matrix of positive integers, determine if there are any "rings" of mountains. The formal definition for this challenge is: given a matrix of positive integers, is there any positive integer n for which there is a closed ring of cells in the matrix that are strictly greater than n such that all cells e... | [] |
Consider a one-dimensional sequence of numbers within a fixed range, i.e.
[1, 2, 4, 6, 8, 0, 2, 7, 3] in range [0, 10⟩
The Ever-Increasing Graph* ** is a line that connects all the points in this sequence left to right, and always goes upwards or stays level. If necessary, the line wraps around from top to bottom and ... | [
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Your task is to write a program or a function that outputs n random numbers from interval [0,1] with fixed sum s.
Input
n, n≥1, number of random numbers to generate
s, s>=0, s<=n, sum of numbers to be generated
Output
A random n-tuple of floating point numbers with all elements from the interval [0,1] and sum of all el... | [] |
Given an integer matrix a and a nonnegative integer i, output a mapping b that maps the distinct values in the ith column of a to rows of a who have that value in the ith column.
You may assume that i is in the half-open range [0, num_cols(a)) (or [1, num_cols(a)] if you choose to use 1-based indices), and that all int... | [
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We all know that a lot of exercises only affect one half of your body, so you have to do them twice, once for each side. Such exercises have two counterparts, one for the left side and one for the right. However, there's no need to execute the two counterparts consecutively, as long as the exercises for both sides are ... | [] |
The task is taken from an MIT lecture by Prof. Devadas called You can read minds. A detailed explanation of the trick can be found in the linked video, or in this document. I'll try to explain it in simpler terms.
It turns out this was invented in the 1930's, and is known as the "Five-Card Trick of Fitch Cheney".
The ... | [] |
There's a type of n×n matrix W called the basic Weyr canonical form. Such a matrix is described by its blocks and has the following properties, using the following reference diagram:
the main diagonal blocks Wii are ni×ni matrices of the form λIni where Ini is the ni×ni identity matrix.
n1 ≥ n2 ≥ ... ≥ nr
the first s... | [] |
Definitions
The kth ring of a square matrix of size N, where 1 ≤ k ≤ ceiling(N/2) is the list formed by the elements of the kth and (N-k+1)th rows and columns, but without the first and last k-1 elements.
Example:
Matrix:
1 2 3 4 5
6 7 8 9 1
8 7 6 5 4
3 2 1 9 8
7 6 5 4 3
Delimited in rings:
+-------------------+
| ... | [] |
Given an array of numbers with length >=3 and length % 3 == 0
[1, 2, 3, 4, ...]
You will split it in sub-arrays of length 3
[[1, 2, 3], [4, 5, ...], [...
And return an array with
[0] => The amount of cases in the sub-array where all numbers are equal
[1] => In case all numbers in sub-array are not equal, the amount ... | [] |
Challenge
Given a sequence of numbers, create a function which returns the sequence steps.
Assume a sequence will be N >= 3
Sequence will repeat it steps at least once
Sequence will only contain natural numbers
Your function or program should return the shortest possible sequence of steps
Example:
Input: [1, 2, 3, 5,... | [] |
Inspiration.
Consider a list l, consisting of numbers. Define a block operation at index i on the list l to be the act of moving 3 consecutive elements starting from i in l to the end.
Example:
l, i (1-indexing) -> l (after applying block operation at index i)
[1,2,3,4,5], 1 -> [4,5,1,2,3]
[1,2,3,4,5,6,7], 3 -> [1,2,6,... | [] |
Background
Nonogram, also known as Picross or Griddlers, is a puzzle where the objective is to determine if each cell on the 2D grid should be colored or left blank, using the numbers of consecutive colored cells on each line.
The following is an example Nonogram puzzle with solution.
The problem is, some commercial N... | [] |
This challenge is really simple (and a precursor to a more difficult one!).
Given an array of resource accesses (simply denoted by nonnegative integers) and a parameter n, return the number of cache misses it would have assuming our cache has capacity n and uses a first-in-first-out (FIFO) ejection scheme when it is fu... | [
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Introduction
In a private chat, a friend of mine apparently recently stumbled across a security system which has the following two restrictions on its valid pins:
Each digit must be unique (that is "1" may only appear once)
The order of the digits doesn't matter ("1234"="4321")
So to illustrate how bad this padlock s... | [] |
Problem Description
Given:
a function \$f(a, b, c, d, e) = \frac{a \times b}c + \frac de\$
an array \$x = [x_1, x_2, x_3, x_4, ..., x_n]\$ of non-distinct integers
a target value \$k\$
What is the most efficient way, in terms of worst-case \$n\$, to find 5 distinct indices \$x_a, x_b, x_c, x_d, x_e\$ from \$x\$ such ... | [
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First, let's talk about Beatty sequences. Given a positive irrational number r, we can construct an infinite sequence by multiplying the positive integers to r in order and taking the floor of each resulting calculation. For example,
If r > 1, we have a special condition. We can form another irrational number s as s =... | [
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I have a simple challenge for you this time. Given an array of positive integers A (or the equivalent in your language), replace each entry Ai with the sum of the next Ai elements of A, cycling back from the beginning if there are not enough items.
As usual, you can compete in any programming language and can take inpu... | [] |
The digital root (also repeated digital sum) of a positive integer is the (single digit) value obtained by an iterative process of summing digits, on each iteration using the result from the previous iteration to compute a digit sum. The process continues until a single-digit number is reached.
For example, the digital... | [
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For the purposes of this question, a deck of cards is formatted in this way:
[
"AS", "2S", "3S", "4S", "5S", "6S", "7S", "8S", "9S", "10S", "JS", "QS", "KS",
"AD", "2D", "3D", "4D", "5D", "6D", "7D", "8D", "9D", "10D", "JD", "QD", "KD",
"AH", "2H", "3H", "4H", "5H", "6H", "7H", "8H", "9H", "10H", "JH", "QH", "K... | [
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Background
In the game of Nim, players alternate removing "stones" from "piles": on each turn, a player must remove between one and all stones from a single pile. The object of Nim is to take the last stone or, in the misere variant, to force your opponent to do so -- however, it turns out the strategies are nearly id... | [
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[
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18,
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Introduction:
Although I originally had a Dutch song in my head, where the lyrics are: "Doe 'n stapje naar voren, en 'n stapje terug" (which translated to "Take a little step forward, and a little step back"), when I searched for the full lyrics, I realized they only got back and forth, and never sideways.
So, instead ... | [
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According to this question a Superb Shuffle™️ is defined as a full deck of cards (including jokers) which follows this set of rules:
No two cards (except Jokers) of the same suit are adjacent.
No card (except Jokers) is adjacent to one of the same value.
No card (except Jokers) is adjacent to one of an adjacent value ... | [
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Challenge
You are given three integers as input - min_value, max_value, sample_size, that you can pass to your answer as either array or several parameters.
Your task is to output a diagram in any convenient format, that shows the frequency of numbers in the (min_value, max_value) range showing up when a random number ... | [] |
Given a pattern (string or array format) of Bits :
[0,1,1,1,0,1,1,0,0,0,1,1,1,1,1,1]
The tasks is to replace any number of consecutive 1-Bits with an ascending number sequence starting at 1.
Input
Pattern (can be received as an string or array) Example:
String: 1001011010110101001
Array: [1, 0, 0, 1, 0, 1, 1, 0, 1,... | [] |
Introduction
In the not so distant future with the AI revolution, we will need a way to solve their captchas to prove we're not humans.
This challenge was inspired by CommitStrip.
Challenge
One such captcha is the challenge of calculating the sum of all odd digits of Pi from digit 1 to digit n, including the first digi... | [] |
I work at a bakery that serves Wheat, Rye, Barley, Grain, and French bread, but the baker's a little weird - he stacks the loaves in random order, and sometimes just leaves some shelves at the end empty.
Each day, the same customer comes in and asks for one of each loaf of bread, but the tricky thing is, he's a germoph... | [
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A perfect square is an integer that is the square of an integer; in
other words, it is the product of some integer with itself.
Calculate the number of perfect squares below a number \$n\$ where \$n\$ will be taken as an input
Examples:
There are 9 perfect squares below 100: 1, 4, 9, 16, 25, 36, 49, 64, 81
Constrain... | [] |
Challenge:
Given a list of nonempty lists of integers, return a list of tuples of the following form: First list tuples starting with each element of the first list followed by the first element of every subsequent list, so the ith tuple should be [ith element of first list, first element of second list, ... , first el... | [] |
Description
OEIS sequence A096004 gives the
Number of convex triangular polyominoes [polyiamonds] containing n cells.
It begins:
1, 1, 1, 2, 1, 2, 2, 3, 2, 2, 2, 3, 2, 3, 3, 5
For example, a(8)=3 with the following three convex polyiamonds:
Input: 8
Output:
*---*---*---*---*
/ \ / \ / \ / \ /
*---*---*---*---*
... | [] |
Defintion
A centrosymmetric matrix is a square matrix that is symmetric about its center. More rigorously, a matrix \$A\$ of size \$n \times n\$ is centrosymmetric if, for any \$i,\: j \in ([1, n] \cap \mathbb{Z})\$ the following relation is satisfied:
$$A_{i,\:j}=A_{n+1-i,\:n+1-j}$$
Examples of such matrices
Here is a... | [] |
...or Toroidal Moore Neighbourhoods
Given positive integers h, w and a non-negative integer i, return all of the indices surrounding i.
You are to assume a matrix consisting of h rows of w elements, numbered from lowest, in the top left-hand corner, to highest, in the bottom right-hand corner, and return, in any reaso... | [] |
Challenge
Given nine numbers, a, b, c, d, e, f, g, h, i, as input which correspond to the square matrix:
$$\mathbf{M} = \begin{pmatrix}a& b& c\\ d& e& f\\ g& h& i\end{pmatrix}$$
Find the inverse of the matrix, \$\mathbf{M}^{-1}\$ and output its components.
Inverse Matrix
The inverse of a matrix 3 by 3 obeys the followi... | [] |
Challenge
Given a list of integers and a velocity, \$v\$, implement a sorting algorithm which simulates a program sorting the list from smallest to biggest at the given velocity.
Einstein's Theory of Special Relativity
What do I mean? Well assume your program takes a time, \$T\$, to sort a particular list. If you ran t... | [] |
This is a 2-dimensional version of this question.
Given a non-empty 2-dimensional array/matrix containing only non-negative integers:
$$ \begin{bmatrix}
{\color{Red}0} & {\color{Red}0} & {\color{Red}0} & {\color{Red}0} & {\color{Red}0} \\
{\color{Red}0} & {\color{Red}0} & 0 & 1 & 0 \\
{\color{Red}0} & {\color{Red}0} & ... | [] |
Motivation: Sometimes certain items in a list don't count towards your totals. For example, counting plane passengers in rows, where babies sit on a parent's laps.
Challenge: write a program to split a list of items into chunks. Each chunk (except possibly the last) is the same size, where size is defined as the number... | [] |
I'm trying to get the shortest way (character possible) to obtain List 3.
List 1 and List 2 are already given to me as arguments and are the same length.
l1 = [1, 2, 3, 4, 5]
l2 = ['a', 'b', 'c', 'd', 'e']
And List 3 should look like (yes, it needs to be a list):
l3 = ['a', 1, 'b', 2, 'c', 3, 'd', 4, 'e', 5]
| [
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Input
A non-empty binary matrix consisting of 3x3 sub-matrices put side by side.
Task
Your task is to identify valid dice patterns (as described below) among the 3x3 sub-matrices. Each valid pattern is worth the value of the corresponding dice. Invalid patterns are worth 0.
Output
The sum of the valid dice values.
Dice... | [] |
You will be given a sequence of memory requests and a cache size. You must return the least possible number of cache misses under any cache replacement strategy.
An optimal strategy is Belady's algorithm, which you can use if you want to.
A caching system works as follows: The cache starts out empty. Memory requests c... | [
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This challenge is based on a sandbox post by user48538. Since he is no longer active on this site, I took over this challenge.
apgsearch, the distributed soup search program for Conway's Game of Life and the search results database, Catagolue use apgcodes to classify and denote patterns. apgcodes themselves use the ex... | [] |
Topically related.
Objective: Given a matrix of positive integers \$M\$, output the smallest centrosymmetric matrix which contains \$M\$ (this matrix may contain non-positive integers as well).
A centrosymmetric matrix is a square matrix with rotational symmetry of order 2—i.e. it remains the same matrix after rotating... | [] |
Not to be confused with Least Common Multiple.
Given a list of positive integers with more than one element, return the most common product of two elements in the array.
For example, the MCM of the list [2,3,4,5,6] is 12, as a table of products is:
2 3 4 5 6
---------------
2 | # 6 8 10 12
3 | # # 12 15 ... | [] |
When you roll a die, you have a 6:1 chance of any given option.
There's a bookmaker taking bets on die rolls. He owns £20 at the start of the game.
The bookmaker offers odds of 4:1, but gamblers take it, because there's money on offer.
There are 10 gamblers. A, B, C, D, E, F, G, H, I, and J. Each gambler owns 10 pounds... | [
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Let \$L\$ be a list of positive integers with no particular ordering, and which can contain duplicates. Write a program or function which outputs a list of positive integers \$M\$ (whose ordering is unimportant) such that merging \$L\$ and \$M\$ results into the smallest list which can entirely split into identical ran... | [
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Introduction:
(Source: Wikipedia)
When we look at a rainbow it will always have the colors from top to bottom:
Red; orange; yellow; green; blue; indigo; violet
If we look at these individual rings, the red ring is of course bigger than the violet ring.
In addition, it's also possible to have two or even three rainbow ... | [] |
Honestly, I can't believe this hasn't already been asked, but here it is
Background
Given a simple undirected planar (the graph can be drawn in the plane without intersections) graph, it is a proven theorem that the graph is 4-colorable, a term we will explore in a bit. However, it's far easier to 5-color a graph, whic... | [] |
Background
Consider the following sequence (A051935 in OEIS):
Start with the term \$2\$.
Find the lowest integer \$n\$ greater than \$2\$ such that \$2+n\$ is prime.
Find the lowest integer \$n'\$ greater than \$n\$ such that \$2 + n + n'\$ is prime etc.
A more formal definition:
$$a_n=\begin{cases}2 & \text{if }n=0 ... | [
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Okay, so I saw this in a meme and decided it'd be the perfect code golf challenge:
I prefer to increase the side of my indents according to the Fibonacci sequence:
class Kls
def method
t = Time.now
if t.hour >= 12
puts "It's afternoon"
if t.hour == 18
puts "It's time for your meal of:"
%w(bre... | [] |
Introduction
There is a group of people that have to cross a rickety bridge that can only support two people at a time. It is a dark and foggy night, but unfortunately, the group only has one lamp. The bridge must be crossed by an individual or pair that is holding the lamp. When a pair is traveling together, they must... | [] |
Given a non-negative integer, \$n\$, yield the \$(n^2)^\text{th } n\$-gonal number.
Further Detail:
The \$x\$-gonal numbers, or polygonal numbers, are also known as the two-dimensional figurate numbers.
Many people will be familiar with the triangular numbers, these are the \$3\$-gonal numbers:
$$F(3,n)=\sum_{i=1}^{n}(... | [] |
Find the runs inside an array
A run is defined as three or more numbers that increment from the previous with a constant step. For example [1,2,3] would be a run with step 1, [1,3,5,7] would be a run with step 2, and [1,2,4,5] is not a run.
We can express these runs by the notation i to j by s where i is the first numb... | [
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You run a political website, and have determined that people have a better intuitive understanding when the chance of winning or losing an election is expressed as a ratio ("5 in 7") than when it is expressed as a percentage ("71%").
But you also don't want to display confusing ratios like "58 in 82", you'd like them ... | [] |
Given an N-dimensional orthogonal (non-ragged) array of non-negative integers, and an indication of which dimensions to reverse, return the array but reversed along those dimensions. The indication may be given as a Boolean list of length N or a list of a subset of the first N dimensions indexed from 0 or 1.
Please sta... | [] |
Introduction:
Inspired by this comment of @MagicOctopusUrn on @Emigna's 05AB1E answer for my "It was just a bug" challenge:
8F9ÝÀNð×ý}».∊ I done did made a spaceship maw! And I was all excited about suggesting a 12-byte edit. – Magic Octopus Urn Jul 17 '17 at 20:10
Which is a 05AB1E (legacy) program resulting in this... | [] |
It is 20th anniversary of Casio's S-VPAM calculators and it is worth celebrating.
Task: Process input string as Casio S-VPAM calculator does. The infix notation and precedence of mathematical operations must be followed. Angle values are expected in radians. Since there were multiple updates, sin 15, sin15 and sin(15 a... | [] |
The Dihedral group \$D_3\$ represents the symmetries of an equilateral triangle, using the identity (represented by id), rotations (represented by r1 and r2), and reflections (represented by s0, s1, and s2).
Your task is to compute the composition \$yx\$ of the elements \$x, y \in D_3 \$. They are given by the Cayley ... | [
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Introduction
For the purposes of this challenge, we will define the neighbours of an element \$E\$ in a square matrix \$A\$ (such that \$E=A_{i,j}\$) as all the entries of \$A\$ that are immediately adjacent diagonally, horizontally or vertically to \$E\$ (i.e. they "surround" \$E\$, without wrapping around).
For peda... | [] |
Challenge:
Given a positive integer, output the longest single-digit subsequence that occurs at least twice, AND has boundaries of another digit (or the start/end of the integer).
An example:
Input: 7888885466662716666
The longest subsequence of a single digit would be 88888 (7[88888]5466662716666) with a length of 5. ... | [] |
Edit: I haven't played D&D before so when I initially made this question I didn't properly research it. I apologize for this, and I'm making a few edits that might invalidate answers to stay as true as possible to the dnd 5e rules. Sorry.
A D&D fan from a recent Hot Network Question seems to have some trouble working ... | [
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Definitions
Quadratic residues
An integer \$r\$ is called a quadratic residue modulo \$n\$ if there exists an integer \$x\$ such that:
$$x^2\equiv r \pmod n$$
The set of quadratic residues modulo \$n\$ can be simply computed by looking at the results of \$x^2 \bmod n\$ for \$0 \le x \le \lfloor n/2\rfloor\$.
The challe... | [
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The ChatRoom is here
I love playing the card game BS, but sometimes, it just doesn't have enough oomph for my short attention span. Instead, let's play some Russian BS.
Rules
Here is a quick guide to the rules.
The game begins with a random player declaring the card type of the round (out of 14 options: A,2,3...10,J,Q... | [] |
In this task your code will be given an integer \$n\$ as input. Your code should then output the greatest number of multiples of \$3\$ that can be concatenated (in base \$10\$) to form \$3n\$ (with no leading zeros). For example if you were given \$26042\$ as input,
\$26042\times3=78126\$
and \$78126\$ can be made ... | [] |
Intro
A friend posed this question today in a slightly different way - "Can a single [Python] command determine the largest of some integers AND that they aren't equal?".
While we didn't find a way to do this within reasonable definitions of "a single command", I thought it might be a fun problem to golf.
Challenge
"R... | [] |
Input:
An integer n in the range 2 <= n <= 10
A list of positive integers
Output:
Convert the integers to their binary representation (without any leading zeroes), and join them all together.
Then determine all binary substrings that form a 'binary fence' using n amount of fence posts. The spaces (zeros) between each... | [] |
Introduction
Large meetings waste working time. Our aim is to split a large meeting into a number of smaller meetings, so the average number topics that a person discusses is minimized but every person has to be in every meeting they are interested in.
Input
Given is a function from a set of topics \$T\$ to a set of pe... | [] |
From this stackoverflow question
Given a 2D array of size \$ M \times N \$, output the values in a anti-clockwise fashion. The output must start from the outside to the inside and the initial point always is going to be \$(0,0)\$.
Example Given:
$$ \begin{bmatrix} \color{blue}1&\color{red}2&\color{red}3&\color{red}4 \\... | [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
],
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
]
] |
Idea:
Consider a 2-bit bitmap of arbitrary side-lengths overlaid on a coordinate grid and imaged with random data (1's represent an element of the image, 0's represent the "blank" canvas background):
y x—0 2 4 6 8 10 14 18
|
0 0000000000111100000000
0000000011111110000000
2 0000111111111111000000
0000... | [] |
Consider an array A of length n. The array contains only positive integers. For example A = (1,1,2,2). Let us define f(A) as the set of sums of all the non-empty contiguous subarrays of A. In this case f(A) = {1,2,3,4,5,6}. The steps to produce f(A) are as follows:
The subarrays of A are (1), (1), (2), (2), (1,1), ... | [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
],
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
]
] |
This question has a similar set up to Find an array that fits a set of sums although is quite different in its goals.
Consider an array A of length n. The array contains only positive integers. For example A = (1,1,2,2). Let us define f(A) as the set of sums of all the non-empty contiguous subarrays of A. In this cas... | [] |
Input
Two lists with binary values (list_a, list_b) of equal length=>3.
Output
Two lists with binary values (smoothed_a, smoothed_b) with minimal Forward Difference while keeping the same sum before and after processing sum(list_a) + sum(list_b) == sum(smoothed_a) + sum(smoothed_b).
Forward Difference being the absolut... | [] |
Isn't it annoying when you're taking a picture, but the background detracts from the actual substance of the image? I'd say it is. I need to know how much I should crop so that I get rid of this problem! But - as usual - I am quite lazy, so I need someone to do this for me...
Task & Rules
Given a binary matrix represe... | [] |
Inspired by this StackOverflow question.
Input:
We'll take three inputs:
A delimiter-character D to split on
A character I between two of which we ignore the delimiter character (I know, that sounds vague, but I'll explain it below)
A string S
Output:
A list/array containing the substrings after the split.
Example:
I... | [] |
(thanks to @JonathanFrech for the title)
Challenge
Write a program or function that, given a collection of positive integers \$S\$ and a positive integer \$n\$, finds as many non-overlapping subcollections \$T_1, T_2, ..., T_k\$ of \$S\$ as possible, such that the sum of every \$T_m\$ is equal to \$n\$.
Example
Given \... | [
[
220,
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220
]
] |
There is a "sorting algorithm" sometimes called Stalin sort in which in order to sort a list you simply remove elements from the list until it is sorted in increasing order. For example the list
[1, 2, 4, 5, 3, 6, 6]
When "sorted" using Stalin sort becomes
[1, 2, 4, 5, 6, 6]
The three was removed because it was out ... | [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
]
] |
Inspired by "You had me at hello"
Introduction
For those who don't know, hexadecimal is a base system like decimal. Contrary to decimal however, it uses 16 (hence the name) digits instead of 10.
Here are the first few numbers while counting up in hexadecimal to maybe give you a feel of things, although you should proba... | [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
],
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
],
[
220,
16,
11,
220,
17,
11,
220,
18,
11,
220... |
Given an array of integers a which contains n integers, and a single integer x; remove the fewest amount of elements from a to make the sum of a equal to x. If no combinations of a can form x, return a falsy value.
As pointed out in a comment this is the maximum set with a sum of x, excuse my lesser math brain. I forg... | [] |
Problem A3 from the 2008 Putnam competition says:
Start with a finite sequence \$a_1, a_2, \dots, a_n\$ of positive integers. If possible, choose two indices \$j < k\$ such that \$a_j\$ does not divide \$a_k\$, and replace \$a_j\$ and \$a_k\$ by \$\gcd(a_j, a_k)\$ and \$\text{lcm}(a_j, a_k)\$, respectively. Prove that... | [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
],
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
],
[
64,
62,
16,
11,
264,
62,
17,
11,
1124,
678... |
Background
A number n can be described as B-rough if all of the prime factors of n strictly exceed B.
The Challenge
Given two positive integers B and k, output the first k B-rough numbers.
Examples
Let f(B, k) be a function which returns the set containing the first k B-rough numbers.
> f(1, 10)
1, 2, 3, 4, 5, 6, 7, 8,... | [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
],
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
]
] |
The 5-card magic trick involves a magician whose assistant gives them 4 shown cards and a hidden one, in this order, and the magician must guess the hidden one.
WARNING: Solution below! Leave now or get spoiled with it.
The solution
The trick here is that the five cards are given in a specific order!
\$c_1,...,c_5\$ a... | [] |
This is a follow up to Count arrays that make unique sets . The significant difference is the definition of uniqueness.
Consider an array A of length n. The array contains only positive integers. For example A = (1,1,2,2). Let us define f(A) as the set of sums of all the non-empty contiguous subarrays of A. In this c... | [] |
Given two integers, output the two integers, and then the range between them (excluding both).
The order of the range must be the same as the input.
Examples:
Input Output
0, 5 -> [0, 5, 1, 2, 3, 4]
-3, 8 -> [-3, 8, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7]
4, 4 -> [4, 4]
4, 5 -> [4, 5]
8, 2 ->... | [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
],
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
],
[
220,
16,
11,
220,
17,
11,
220,
18,
11,
220... |
Consider an array A of length n. The array contains only integers in the range 1 to s. For example take s = 6, n = 5 and A = (2, 5, 6, 3, 1). Let us define g(A) as the collection of sums of all the non-empty contiguous subarrays of A. In this case g(A) = [2,5,6,3,1,7,11,9,4,13,14,10,16,15,17]. The steps to produce g(A... | [] |
Matlab has a useful command for visualizing data: plot. It draws data points using "markers" in 2-D space, connecting them with lines; however, for this challenge, let's ignore the lines and use only markers. In fact, only one marker.
Input: one of Matlab's marker symbols: . o x + * s d v ^ < > p h
Output: correspondin... | [] |
Given a non-empty rectangular array of integers from 0 to 9, output the amount of cells that are 8 and do not have a neighbour that is 8. Neighbouring is here understood in the Moore sense, that is, including diagonals. So each cell has 8 neighbours, except for cells at the edges of the array.
For example, given the in... | [] |
Shorter version of Skyscrapers Challenge
Task
Given an array of building heights and a positive integer k, find all the permutations(without duplicates) of the heights such that exactly k buildings are visible.
Any building will hide all shorter or equal height buildings behind it.
Any format for input and output is va... | [] |
The Dirichlet convolution is a special kind of convolution that appears as a very useful tool in number theory. It operates on the set of arithmetic functions.
Challenge
Given two arithmetic functions \$f,g\$ (i.e. functions \$f,g: \mathbb N \to \mathbb R\$) compute the Dirichlet convolution \$(f * g): \mathbb N \to \m... | [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
],
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
]
] |
As with most APL symbols, ⍉ has different meanings when called with one argument (transpose) versus two arguments (dyadic transpose / reorder dimensions). This challenge concerns the latter, which acts similarly to numpy.moveaxis in Python or permute in MATLAB, but is more powerful.
order ⍉ A when order has distinct en... | [] |
Given integer n, calculate a set of n random unique integers in range 1..n^2 (inclusive) such that the sum of the set is equal to n^2
Random, in this case, means uniformly random between valid outputs. Each valid output for a given n must have a uniform chance of being generated.
For example, n=3 should have a 1/3 chan... | [
[
11,
220,
16,
11,
220,
17,
11,
220,
18,
11,
220,
20,
11
]
] |
This is a restricted-source, kolmogorov-complexity, code-golf challenge to produce a fixed output with no input.
The output format, however, is flexible - it may be printed to standard out, printed to standard error, returned as a list of characters, returned as a list of bytes, or returned as a list of integers. If yo... | [
[
220,
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220
]
] |
Here are the annual returns for a hypothetical S&P 500 stock index fund for each calendar year from 1928 to 2017, expressed as a multiplier. So in 1928 you might say "the index went up by 37.88%" which I've represented here by 1.3788.
1.3788, 0.8809, 0.7152, 0.5293, 0.8485, 1.4659, 0.9406, 1.4137, 1.2792, 0.6141, 1.25... | [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
],
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
],
[
220,
16,
11,
220,
17,
11,
220,
18,
11,
220... |
For nandgame fans: Please try out DPD to decimal in logic gates too!
Background
Densely packed decimal (DPD) is a way to efficiently store decimal digits in binary. It stores three decimal digits (000 to 999) in 10 bits, which is much more efficient than naive BCD (which stores one digit in 4 bits).
Notations
The lo... | [] |
The task
Given the set
$$S = \left[{1,2,3,4,5,6,7,8}\right]$$
and an integer
$$0 \leq N < 2^{|S|}$$
find the Nth subset.
Input/Output
N is given as an unsigned integer on stdin. You must print the Nth subset in a format suitable for your language (this may include [1,2,3],{1,2,3},[1, 2, 3],1 2 3,1,2,3 etc. for as long... | [] |
Peg solitaire is a popular game usually played alone. The game consists of some number of pegs and a board which is divided into a grid - usually the board is not rectangular but for this challenge we will assume so.
Each valid move allows one to remove a single peg and the goal is to play in a way, such that there is ... | [] |
Inspired by recent popularity of nandgame on TNB, and my own previous challenge.
Background
Densely packed decimal (DPD) is a way to efficiently store decimal digits in binary. It stores three decimal digits (000 to 999) in 10 bits, which is much more efficient than naive BCD (which stores one digit in 4 bits).
Convers... | [] |
Summary
A teacher was told to prepare word problems for the students. She is given a list of equations and told to write them as the corresponding word problem. However, she is very lazy, so she doesn't put much creativity into it. Instead, she simply writes it literally. For example, when she reads 1+1, she writes one... | [] |
Goal
The goal of this challenge is to produce a function of n which computes the number of ways to partition the n X 1 grid into triangles where all of the vertices of the triangles are on grid points.
Example
For example, there are 14 ways to partition the 2 x 1 grid, so f(2) = 14 via the following partitions
where t... | [] |
Challenge
Mark is a student who receives his N marks in a concatenated way in a one single line.
The challenge is to separate his marks, knowing that each mark can only be 0 or 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10.
Input
N natural number and one line.
Output
A set of natural numbers.
Example
N, One line-----... | [] |
Given an input n, write a program or function that outputs/returns the sum of the digital sums of n for all the bases 1 to n.
$$n + \sum_{b=2}^n \sum_{i=0}^\infty \left\lfloor \frac{n}{b^i} \right\rfloor \bmod b$$
Example:
n = 5
Create the range [1...n]: [1,2,3,4,5]
For each element x, get an array of the base-x digi... | [] |
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 inits.)
Details
The input list contains numbers (or another type if more convenient).
The output must be a list of lists.
The submission can, but does not... | [] |
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 output should be validated against the 64-bit signed integer representation of the number, regardless of language
Default code... | [] |
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