instruction_seed stringlengths 292 48.7k | found_ngrams listlengths 0 21 |
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The treewidth of an undirected graph is a very important concept in Graph Theory. Tons of graph algorithms have been invented which run fast if you have a decomposition of the graph with small treewidth.
The treewidth is often defined in terms of tree decompositions. Here's a graph and a tree decomposition of that grap... | [] |
What you need to do is create a function/program that takes a decimal as input, and outputs the result of repeatedly taking the reciprocal of the fractional part of the number, until the number becomes an integer.
More specifically, the process is as follows:
Let x be the input
If x is an integer, output it.
Otherwise... | [] |
This is a very very simple algorithm, that I am sure can be solved in many many different languages. In Spain ID cards (known as DNI) consist of 8 numbers and a control character. The control character is calculated with the following algorithm: divide the number by 23, take the remainder of the operation and replace i... | [] |
Inspired by the bugged output in @Carcigenicate's Clojure answer for the Print this diamond challenge.
Print this exact text:
1 2 3 4 5 6 7 8 9 0
1 2 3 4 5 6 7 8 9 0
1 2 3 4 5 6 ... | [] |
Compress a sparse matrix using Compressed sparse row (CSR, CRS or Yale format).
These are all the same form of compression (ignore new Yale).
Input may be any 2d data structure (list of lists, etc): e.g
[[0 0 0 0],
[5 8 0 0],
[0 0 3 0],
[0 6 0 0]]
And the output should be three 1d data structures (list etc), that d... | [] |
Continuing my It was just a bug challenge:
Input:
A string consisting of printable ASCII characters without white-spaces nor new-lines.
Output:
First turn the input into a palindrome by reverting the input, and adding it before itself, excluding the middle character (i.e. with an input 1234567890, it will becomes 09876... | [] |
Given a positive integer n ≤ 500:
Find the smallest positive integer k such that all digits in the decimal representation of n*k are either 0 or d, with 1 ≤ d ≤ 9.
Print or return d in less than 30 seconds (read more about that in the Clarifications and rules section).
Easy examples
Here are the first 30 values of d.... | [] |
If we write a sequence of numbers as the coefficients of a power series, then that power series is called the (ordinary) generating function (or G.f.) of that sequence. That is, if for some function F(x) and series of integers a(n) we have:
a(0) + a(1)x + a(2)x^2 + a(3)x^3 + a(4)x^4 + ... = F(x)
Then F(x) is the gener... | [
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[
11,
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19,
11,... |
The task is to find a non-trivial factor of a composite number.
Write code that finds a non-trivial factor of a composite number as quickly as possible subject to your code being no more than 140 bytes long. The output should just be the factor you have found.
Your code can take input and give output in any way that i... | [] |
You are going to participate in a gameshow. One of the challenges works as follows:
The first room contains a large number of identical balls.
The second room contains a series of chutes, each of which has a sensor which counts how many balls have been placed in it. A ball which is placed in a chute cannot then be rec... | [] |
Task
Write a program that will take (as input) a positive integer. It will then count up from 0, appending each integer to a String, only continuing if the length of the String is less than the value of the input.
A serialized integer is defined as the fully-formed integer with the maximum value belonging to the Strin... | [] |
An integer is binary-heavy if its binary representation contains more 1s than 0s while ignoring leading zeroes. For example 1 is binary-heavy, as its binary representation is simply 1, however 4 is not binary heavy, as its binary representation is 100. In the event of a tie (for example 2, with a binary representation ... | [] |
The first two MU-numbers are 2 and 3. Every other MU-number is the smallest number not yet appeared that can be expressed as the product of two earlier distinct MU-numbers in exactly one way.
Here are the first 10
2, 3, 6, 12, 18, 24, 48, 54, 96, 162
Task
Given a positive number calculate and output the nth MU-number... | [] |
There are lots of challenges that just pick a sequence from oeis and ask you to print n-th number or first n numbers or whatever.
It's time to stop automate!
Task
Your task is to parse a sequence page from oeis.org and print its index, description and example values. The page's index should be chosen and random, sele... | [
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16,
11,
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18,
11,
220
]
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Imagine a histogram. Pour an infinite amount of water on to it. Then stop. How much water does the histogram hold?
Let's say we have a histogram with columns of these heights:
1 3 2 1 4 1 3
That would look like this:
#
# # #
## # #
#######
1321413
If we pour an infinite amount of water on this histogram, some ... | [] |
Background
I play D&D on a regular basis with some friends. While talking about the complexity of some systems/versions when it comes to rolling dice and applying bonuses and penalties, we jokingly came up with some additional complexity for dice rolling expressions. Some of them were too outrageous (like extending sim... | [
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18,
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220,
20
],
[
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17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
]
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Seahorses, of course, need shoes. However, a seahorse, having just one tail, needs just one shoe. Unfortunately, the shoes only come in pairs. Money is tight for the seahorse government, so they need to buy as few pairs as possible. Each seahorse has a shoe size x where x is a positive integer. However, a seahorse can ... | [] |
Lets take a set of integers greater than 1 and call it X. We will define S(i) to be the set of all members of X divisible by i where i > 1. Would like to choose from these subsets a group of sets such that
Their union is the set X
No element of X is in two of the sets.
For example we can regroup {3..11} as
... | [] |
Many of us are familiar with the game Tron. You control a "lightcycle" placed on a grid. The lightcycle always moves forward (though you control the direction) and leaves a permanent trail behind it. If you run into a trail, you crash!
The goal here is to determine if a given path is a valid loop, that is, it returns t... | [] |
Introduction
Classically, booleans are one bit; true or false, 1 or 0. Leading zeros would just be redundant. For example, 001 means the same as 00001 or just 1.
The 32-bit boolean
Given a truthy/falsey value, output the equivalent 32-bit boolean as a string.
(Or as a number if for some reason your language supports l... | [] |
We are all familiar with the famous Fibonacci sequence, that starts with 0 and 1, and each element is the sum of the previous two. Here are the first few terms (OEIS A000045):
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584
Given a positive integer, return the closest number of the Fibona... | [
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220,
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17,
11,
220,
18,
11,
220
],
[
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16,
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220,
17,
11,
220,
18,
11,
220,
20
],
[
11,
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16,
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220,
17,
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220,
18,
11... |
Description:
A non-integer representation of a number uses non-integer numbers as the bases of a positional numbering system.
e.g. Using the golden ratio (the irrational number 1 + √5/2 ≈ 1.61803399 symbolized by the Greek letter φ) as its base, the numbers 1 to 10 can be written:
Decimal Powers of φ Base φ... | [] |
According to me, a tornado looks like this:
########
#######
######
#####
####
###
##
#
This tornado starts out with width n, and on each next line, a character is removed from either the left or the right, depending on the input.
Input
The input will be a list of some sort of any two unique values (... | [] |
There have been a billion iterations of Fibonacci challenges on this website, so lets spice things up with a Fibonacci challenge of a billion iterations!
Your challenge is to output the first 1000 decimal digits of the 1,000,000,000th Fibonacci number with as short a program as possible. This may then optionally be fol... | [] |
Imagine a straight river and a road that goes across the river n times through bridges. The road does not loop on itself and is infinitely long. This road would be considered an open meander. An open meander is an open curve, that does not intersect itself and extends infinitely at both ends, which intersects a line n ... | [
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220,
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11,
220,
16,
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220,
17,
11,
220,
18,
11,
220
]
] |
Given an integer n ≥ 1, output a 2D representation† of a percent sign of width n. The construction goes as follows:
Create an n by n matrix (or list of lists) filled with zeroes.
Insert ones in the top-left and bottom-right corners.
Place ones on the diagonal from the bottom-left to the top-right.
For input n = 4, th... | [] |
Challenge
Given a list of integers, return the list of these integers after repeatedly removing all pairs of adjacent equal items.
Note that if you have an odd-length run of equal numbers, one of them will remain, not being part of a pair.
Example:
[0, 0, 0, 1, 2, 4, 4, 2, 1, 1, 0]
First, you should remove 0, 0, 4, 4,... | [] |
A curve is a set of points on a square grid such that each point has exactly two neighbors in the four-neighbor neighborhood and the points form a single connected component. That is, the graph induced by the points on a grid graph is isomorphic to a single cycle. "Induced" means that two points cannot touch in the inp... | [] |
Your task today is to apply a wave to an array of numbers. A wave looks like this: [1, 0, -1, 0, 1, 0, -1, 0, 1...] Applying it to a given array means adding together the first elements, the second elements, etc.
More precisely:
Your program or function will receive an array of integers. It must print or return an equa... | [] |
Challenge
Given a set T of subsets of a finite set S={1,2,3,...,n}, determine whether T is a topology or not.
Explanation
The powerset P(S) of some set S is the set of all subsets of S. Some examples:
S = {}, P(S) = {{}}
S = {1}, P(S) = {{}, {1}}
S = {1,2}, P(S) = {{}, {1}, {2}, {1,2}}
S = {1,2,3}, P(S) = {{}, {1}, {2}... | [] |
(inspired by Helka's response to my random pairing of "chess" and "Fibonacci" tags in chat)
Fibonacci
The Fibonacci numbers are one of the more well-known sequences in mathematics, where each number is composed by adding the two previous numbers together. Below is a definition of the zero-indexed sequence:
f(0) = 0
f(... | [
[
220,
16,
11,
220,
16,
11,
220,
17,
11,
220,
18,
11,
220
],
[
16,
11,
220,
16,
11,
220,
17,
11,
220,
18,
11,
220,
20
],
[
11,
220,
16,
11,
220,
17,
11,
220,
18,
11... |
Your challenge is to generate this string:
0110101101011010011010110101101011010110101101001101011010110100110101101011010110101101011010011010110101101001101011010110101101011010110100110101101011010000110101101011010011010110101101011010110101101001101011010110100110101101011010110101101011010011010110101101001101011... | [] |
Related: Tell me how many math problems I have to do!
Challenge
Given a strictly positive strictly ascending integer list L and an integer 3 ≤ N ≤ length of L, replace the middle integers of L's consecutive integer runs of length ≥ N with a single dash -.
Rules
Horizontal whitespace is irrelevant.
You may optionally p... | [] |
Challenge
Given a matrix M with r rows and c columns, and two Boolean lists V of length r and H of length c, calculate the partitioned cumulative vertical and horizontal sums.
Rules
r and c are greater than or equal to one
H and V begin with a true value
The values in M are within your language's reasonable numeric do... | [] |
Given two lists of dice rolls for a battle in Risk, your program or function must output how many troops each player loses.
Background
You do not have to read this, for it is merely background. Skip to "Task" subheading to continue unabated.
In the game of Risk, one player can attack another player (in fact, this is ... | [] |
You will be given as input an integer k in the range from -4503599627370496 (−252) to 4503599627370496 (252). As is well known, integers in this range can be represented exactly as double-precision floating-point values.
You should output the Hamming weight (number of ones) of the encoding of k in binary64 format. Thi... | [] |
Given a list of non-negative integers in any reasonable format, iterate over it, skipping as many elements as every integer you step on says.
Here is a worked example:
[0, 1, 0, 2, 5, 1, 3, 1, 6, 2] | []
^ First element, always include it
[0, 1, 0, 2, 5, 1, 3, 1, 6, 2] | [0]
^ Skip 0 elements
[0, 1, 0, 2, 5, 1, 3... | [
[
16,
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17,
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18,
11,
220,
19,
11,
220,
20
],
[
220,
15,
11,
220,
16,
11,
220,
16,
11,
220,
18,
11,
220
],
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11... |
Fermat numbers are positive integers that can be expressed as 22x+1 with an integer x.
Let us now define an attribute of a number called "Fermat-ness":
The Fermat-ness of the number is one less than the length of the chain of powers of two, starting from the base, with powers of two expanded so as to maximize the ferm... | [] |
We are going to fold a list of integers. The procedure to do so is as follows, If the list is of even length, make a list of half of its length where the nth item of the new list is the sum of the nth item of the old list and the nth-to-last item of the old list. For example if we had the list
[1 2 3 4 5 6 7 8]
We ... | [] |
Given a positive integer n as input, output the reversed range sum of n.
A reversed range sum is created by making an inclusive range up to n, starting with 1 and including n, reversing each of the numbers inside, and summing it.
Example:
Here is what would happen for an input of 10:
Range: [1,2,3,4,5,6,7,8,9,10]
Rever... | [] |
Oh no, I am lost on the way to finding the great treasures of Marakov! And all I have are these useless instructions that look like S10R10D30... I have no idea what they mean! Can you help me?
Challenge
Given directions consisting of N E S W U D L R 1 2 3 4 5 6 7 8 9 0, output how far I will be from where I started whe... | [] |
Inspired by this, this and this.
So, now that the evil farmer has set your field on fire, you naturally want to put it out. You have a bunch of friends who all have buckets, and you want a program to figure out where to place everyone to save as much of your wheat as possible.
Your Task:
Write a program or functio... | [] |
Given an unsigned 16-bit integer N, your task is to determine whether its binary representation mapped inside a 4x4 matrix is matching a tetromino shape, and if so, which shape it is.
Matrix
Each bit of N is mapped inside a 4x4 matrix, from left to right and from top to bottom, starting with the most significant one.
E... | [] |
Lost is a 2-D programming language where the start position and direction of the ip are entirely random.
This makes it very difficult to make deterministic Lost programs. However today we are not writing a deterministic program, we are writing an RNG.
Write a Lost program that takes no input and outputs a single digit... | [] |
Challenge description
In taxicab metric, a distance between two points is defined as:
Consider a matrix with only zeros and ones:
0 0 0 1 0
1 0 0 0 0
0 0 0 0 0
1 0 0 1 0
1 0 0 0 0
Let's map each 1 to the distance to nearest different 1 in the matrix (of course, assuming that distance between two adjacent rows/column... | [] |
Challenge
Here at PPCG, we sure do like our sequences, so here's a fun another one.
Let's define a(n) as being the smallest non-negative integer X that is not equal to any a(k) (0 < k < n), and a(n-1) and X do not share any decimal digits. a(0) = 0
Given an input n > 0, output such a(n).
For example, for input n = 13, ... | [
[
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11,
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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... |
Everybody knows pi the mathematical constant, the ratio of a circle's circumference to its diameter.
3.14159265358979323846264338327950288419716939937510...
You probably also know e the mathematical constant, the base of a natural logarithm.
2.71828182845904523536028747135266249775724709369996...
But... do you know p... | [] |
Given a string S and a list of indices X, modify S by removing the element at each index of S while using that result as the new value of S.
For example, given S = 'codegolf' and X = [1, 4, 4, 0, 2],
0 1 2 3 4 5 6 7 |
c o d e g o l f | Remove 1
c d e g o l f | Remove 4
c d e g l f | Remove 4
c d e g f ... | [] |
The coefficient of relationship refers to how much DNA two persons have in common. A parent has 50% common DNA with their child (unless the parents are related), so to calculate it we have to find all pairs of directed disjoint paths starting at same node (common ancestor) and ending at each of the two siblings, and su... | [] |
Given as input a positive integer n>=1, output the first n rows of the following triangle:
1
1 0 1
0 0 1 0 0
1 1 1 0 1 1 1
0 0 0 0 1 0 0 0 0
1 1 1 1 1 0 1 1 1 1 1
0 0 0 0 0 0 1 0 0 0 0 0 0
1 1 1 1 1 1 1 0 1 1 1 1 1 1 1
0 0 0 0 0 0... | [] |
Given positive integer n > 2. We convert it to an array as follows:
If it is equal to 2 return an empty array
Otherwise create array of all n's prime factors sorted ascending, then each element replace with its index in prime numbers sequence and finally convert each element to array
For example, lets convert number ... | [] |
The title is valid Jelly Code which has the same output as L€€ except printed twice.
Background
You can skip this section without losing ability to complete the challenge
Some operations in Jelly try to convert its argument to a list first before applying the operation. One example is €, the mapping quick. This some... | [] |
Warning : this is NOT a "hey, let's draw a cake in ASCII-art" challenge! Please keep reading ;)
Some time ago it was my birthday, I'm 33 now.
So there is this awkward social tradition consisting in inviting family and friends, putting number-like candles on a cake, sing songs and open gifts.
33
--------
Instead... | [] |
Let us say a substring is any continuous section of an original string. For example cat is a substring of concatenate. We will say that a proper substring is a substring that is not equal to the original string. For example concatenate is a substring of concatenate but not a proper substring. (single character strin... | [] |
We've had a few challenges for base conversion, but all of them seem to apply to integer values. Let's do it with real numbers!
The challenge
Inputs:
A real positive number x, expressed in base 10. This can be taken as a double-precision float or as a string. To avoid precision issues, the number can be assumed to be ... | [] |
Make a program/function which takes in an integer from 0 to 999999999999 (inclusive) as input and returns how many syllables it has when spoken in English. Make your code short.
Specification
A billion is a thousand million, a trillion is a million million, etc.
A million has three syllables -- it's mill-ee-on, as opp... | [] |
There is a game called Get Home that is played on the a chess board. In this game there is a single piece that is moved by both players in turns. There are some rules to how the piece can be moved. On a turn a player must make one of the following moves for positive n.
n spaces up
n spaces to the left
n spaces up a... | [] |
I ran into this problem while working on another challenge I'm making for this site. In that challenge I utilize "Mario Kart 8 Scoring". The amount of points the player in kth place gets is represented by this 1-indexed array: [15,12,10,9,8,7,6,5,4,3,2,1]. So 1st place gets 15 points, 2nd place gets 12 points, etc.
It... | [] |
Input:
We take two inputs:
An input b with two distinct values: Left and Right.†
And a positive integer n.
Output:
Based on the Left/Right input, we output either of the following two sequences in the range of 1-n (in the sequences below the first 125 items are displayed):
Left:
1, 6, 7, 56, 57, 62, 63, 960, 961, 96... | [
[
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
]
] |
Given an array of non-negative integers, your task is to only keep certain elements of it, as described below.
Let's say the array is [1, 3, 2, 4, 11, 5, 2, 0, 13, 10, 1].
First get the first element of the array, n. Keep the first n elements and discard the next one (discard the n+1th). The new array is [1, 2, 4, 11... | [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
]
] |
Let's count...
Count up to 2 and back to 1
Count up to 4 and back to 1
Count up to 6 and back to 1
... ok you got it...
put all these together and you'll get the following sequence
{1,2,1,2,3,4,3,2,1,2,3,4,5,6,5,4,3,2,1,2,3,4,5,6,7,8,7,6,5,4,3,2,1,2,3...}
Challenge
Given an integer n>0for 1-indexed (or n>=0 for 0-i... | [] |
This challenge is based on a drinking game. I advise against alcohol consumption while programming.
In this game, the players count up in turns: the first player says 1, the second says 2 and so on. Here's the twist however: each number that is divisible by 7 or has a 7 in its digits (in base 10) is replaced by another... | [] |
Primes are everywhere...
they hide inside Pi
3.1415926535897932384626433832795028841971693993751
Let's get those primes!
The Challenge
Given as input an integer n>0, find out how many primes are hidden inside the first n digits of Pi
Examples
For n=3 we should search for primes in [3,1,4]. There are 2 Primes (3,31), so... | [] |
Cut a boolean matrix in 4x2 blocks and render them as Braille characters U+2800...U+28FF.
[[0,1,0,0,1,0],
[1,0,0,0,0,0],
[1,0,0,0,1,0],
[1,1,1,1,0,0]]
⣎⣀⠅
Pad with 0-s if dimensions are not multiples of 4 and 2.
[[0,1,0],
[1,0,0],
[1,1,1]]
⠮⠄
Usual golfing rules apply, flexible on input format. Output should e... | [] |
Inspired by a question at Stack Overflow.
Given a non-empty array of integers x and a positive integer n, compute the sum of each sliding block of length n along the array x, circularly filling the missing values at the left with values from the right as follows:
the first block contains the first entry of x, preceded... | [] |
Earlier I defined the process of crushing an array
In a crush we read the array left to right. If at a point we encounter two of the same element in a row we remove the first one and double the second one.
For example here is the process of crushing the following array
[5,2,2,4]
^
[5,2,2,4]
^
[5,2,2,4]
^
[5... | [] |
Inspired (with the explanation stolen from) this
Background
Say you have two lists A = [a_1, a_2, ..., a_n] and B = [b_1, b_2, ..., b_n] of integers. We say A is potentially-divisible by B if there is a permutation of B that makes a_i divisible by b_i for all i. The problem is then: is it possible to reorder (i.e. perm... | [] |
Convert a binary number (of any size) into a hexadecimal number.
Input
A POSITIVE binary number with just the 0s and 1s. A valid input will always match the following regex: [0-1]+. If the input is not a valid binary number, that is, anything not matching this regex, the output should be 0 or the program should exit,... | [] |
Given the written, spelled-out representation of an integer from 1 to 10^15-1 inclusive, convert it to an actual integer in decimal.
Input Format
The input will always be a string of groups, where each group is composed only of letters and spaces(). The groups are separated by commas.
You may choose whether you want t... | [] |
Input:
A string
Output:
1) First we take remove character at the end of the input-string until we are left with a length that is a square (i.e. 1, 4, 9, 16, 25, 36, etc.)
So abcdefghijklmnopqrstuvwxyz (length 26) becomes abcdefghijklmnopqrstuvwxy (length 25).
2) Then we put this in a square, one line at a time, left t... | [] |
Given an array of positive integers, output a stable array of the distinct prime factors of these integers. In other words, for each integer in the input in order, get its prime factors, sort them, and append any primes not already in the output to the output.
Test Cases
[1,2,3,4,5,6,7,8,9,10] -> [2,3,5,7]
[10,9,8,7,6,... | [] |
Given a positive input number \$n\$, construct a spiral of numbers from \$1\$ to \$n^2\$, with \$1\$ in the top-left, spiraling inward clockwise. Take the sum of the diagonals (if \$n\$ is odd, the middle number \$n^2\$ is counted twice) and output that number.
Example for \$n = 1\$:
1
(1) + (1) = 2
Example for \$n =... | [] |
The partition number of a positive integer is defined as the number of ways it can be expressed as a sum of positive integers. In other words, the number of integer partitions it has. For example, the number 4 has the following partitons:
[[1, 1, 1, 1], [1, 1, 2], [1, 3], [2, 2], [4]]
Hence, it has 5 partitions.
This... | [] |
A game of 2048 goes like this:
Every move you get another piece - either 2 90% of the time, or 4 10% of the time
for each 2 equal pieces combined you get a piece of the sum of the two and the sum gets added to your score
Your task
given a board of a 4x4 game, give the average score of what A game like that would resu... | [] |
Haskell has tuples that can be written as
(a,b,c)
However this is just syntactic sugar for
(,,)a b c
In general an n tuple can be formed with n-1 ,s between (...) followed by its elements separated by spaces. For example the 7-tuple, (1,2,3,4,5,6,7) can be formed by
(,,,,,,)1 2 3 4 5 6 7
Since Haskell does not have... | [] |
When you edit a post on SE, any further edits within a 5-minute grace period are merged into it. Given a list of times you edit a post, count the edits not in a grace period.
Say you edit at minutes [0,3,4,7,9,10,11,12]. This results in 3 edits at times [0,7,12], with the rest happening in their grace periods.
0: [3,4... | [
[
11,
220,
16,
17,
11,
220,
16,
19,
11,
220,
16,
21,
11
],
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
],
[
220,
16,
17,
11,
220,
16,
19,
11,
220,
16,
... |
Introduction
This is a log of length 5:
#####
I want to pile a bunch of these logs on top of each other.
How I do this is that I slide a new log onto the topmost one from the right, and stop sliding when their left or right ends align (don't ask why).
If the new log is longer, it slides all the way to the left end of ... | [] |
Background
We all know the famous Fibonacci sequence, where each term is the sum of the previous two, with the first term being 0 and the second one being 1. The first few elements are:
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765
What we are going to implement today is a si... | [
[
220,
16,
11,
220,
16,
11,
220,
17,
11,
220,
18,
11,
220
],
[
16,
11,
220,
16,
11,
220,
17,
11,
220,
18,
11,
220,
20
],
[
11,
220,
16,
11,
220,
17,
11,
220,
18,
11... |
Specifications
For this challenge, you will be given a matrix of some sort in any reasonable format for a 2-D array. For each row except the last, in order from top (first) to bottom (last), rotate the row below it by x to either direction (you choose a consistent direction to use) where x is the first element in the c... | [] |
Based on this Math.SE question; number copied from this answer. Number originally from a Numberphile video, of course.
Your task is to output the following 1350-digit prime number:
8888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888881111111111111111111111118888881111111111111111... | [] |
This is how the Kolakoski sequence (OEIS A000002) is defined:
The Kolakoski sequence is a sequence that contains 1 and 2, and the nth element of the sequence is the length of the nth group of equal elements (run) in the sequence itself. The first 20 terms of the sequence and the respective lengths are:
1 2 2 1 1 2 1 2... | [] |
Background
The deltas of an array of integers is the array formed by getting the differences of consecutive elements. For example, [1, 2, 4, 7, 3, 9, 6] has the following deltas: [1, 2, 3, -4, 6, -3].
We will now define the deltas of a matrix of integers as the deltas of each row and each column it contains.
As an exam... | [] |
Inspired by this
In the linked challenge, we are asked to apply addition to the elements of the original and the reverse of the input array. In this challenge, we are going to make it slightly more difficult, by introducing the other basic math operations.
Given an array of integers, cycle through +, *, -, //, %, ^, wh... | [
[
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
]
] |
In math, one way to figure out what the type of a given relation (linear, quadratic, etc) is to calculate the differences. To do so you take a list of y values for which the gap between the correspondent x values is the same, and subtract each one from the number above it, creating a list of numbers one shorter then t... | [] |
Specs
You have a cubic 3D space x,y,z of size S integer units, such as 0 <= x,y,z <= S.
You get from default input methods an array of points P represented as x,y,z integer coordinates, in any reasonable format as you like, for example: [x1,y1,z1],[x2,y2,z2],[x3,y3,z3] ... [xn,yn,zn].
All the P values will be in the ... | [] |
Given a rectangular matrix of elevations, draw its contours.
Task
Two elements x and y are on the same contour level if floor(x/10) == floor(y/10). For example, 52 and 58 are on the same contour level, but 58 and 64 are not.
The act of drawing contours is defined as follows:
For every element e, replace it with a two-c... | [] |
I have a stupid old alarm clock with two buttons: hour and minute. The hour button increments the hour of a set alarm, and minute increments the minute time of a set alarm. However, some smart designers realized that pressing both buttons at the same time should have a meaning, and decided that pressing hour and minute... | [] |
We have a floating point number r between 0 and 1, and an integer p.
Find the fraction of integers with the smallest denominator, which approximates r with at least p-digit precision.
Inputs: r (a floating point number) and p (integer).
Outputs: a and b integers, where
a/b (as float) approximates r until p digits.
b... | [] |
Your challenge today is to take an array, split it into chunks, and add those chunks.
Here's how this works: Your program or function will be given an array of integers a and a chunk size L. The array should be split into arrays of size L, if the array length is not divisible by L then the array should have 0's appende... | [] |
An insignificant array is an array of positive integers, where the absolute differences between consecutive elements are all smaller than or equal to 1.
For example, the following array is insignificant:
[1, 2, 3, 4, 3, 4, 5, 5, 5, 4]
Because the corresponding (absolute) differences are:
[1, 1, 1, 1, 1, 1, 0, 0, 1]
W... | [
[
220,
16,
11,
220,
16,
11,
220,
17,
11,
220,
18,
11,
220
],
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
],
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11... |
Let me introduce you to GAU numbers
GAU(1) = 1
GAU(2) = 1122
GAU(3) = 1122122333
GAU(4) = 11221223331223334444
GAU(6) = 11221223331223334444122333444455555122333444455555666666
...
GAU(10) = 112212233312233344441223334444555551223334444555556666661223334444555556666667777777122333444455555666666777777788888... | [] |
Introduction
You can skip this part if you already know what a cyclic group is.
A group is defined by a set and an associative binary operation \$\times\$ (that is, \$(a \times b) \times c = a \times (b \times c)\$. There exists exactly one element in the group \$e\$ where \$a \times e = a = e \times a\$ for all \$a\$ ... | [] |
Inspired by Generate Keyboard Friendly Numbers.
Background
Many number pads have the following layout:
789
456
123
0
We define a number's neighborhood as the set of cells orthogonally adjacent to it on the numpad shown, including itself. For example, 2's neighborhood is {1,5,3,0,2} and 0's neighborhood is {1,2,... | [
[
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
]
] |
Challenge
Given a binary matrix and a binary string, determine if that binary string can be found starting at any point in the matrix and moving in any direction at any subsequent point to form the binary string. That is, can the string be found folded up however inside the matrix?
The string can only be folded at 90 d... | [] |
While doodling around with numbers, I found an interesting permutation you can generate from a list of numbers. If you repeat this same permutation enough times, you will always end up back at the original array. Let's use the following list:
[1, 2, 3, 4, 5]
as an example
Reverse the array. Now our array is
[5, 4, 3,... | [
[
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
]
] |
Take two inputs, a non-empty vector/list containing digits 1 and 2 and a string (no, you may not take 0/1 instead). The string will be one of the following (in lowercase, exactly as written below:
increasing
decreasing
ones
twos
all
none
If the string is ____ then you shall return the indices ___:
increasing ... wher... | [
[
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 two positive integers a and b, output the frequency distribution of rolling a b-sided die a times and summing the results.
A frequency distribution lists the frequency of each possible sum if each possible sequence of dice rolls occurs once. Thus, the frequencies are integers whose sum equals b**a.
Rules
The fre... | [
[
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
]
] |
You deal cards labeled 0 to 9 from a deck one a time, forming stacks that start at 0 and count up by 1.
When you deal a 0, you place it on the table to start a new stack.
When you deal any other card, you stack it atop a card that's exactly
one lower in value, covering it. If there's no such card, the deck isn't stac... | [
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
]
] |
I guess I'm not the only one who have seen this kind of image on Facebook (and other sites).
The picture above was posted 16 days ago, and has accumulated 51 k comments. Some answers: 0, 4, 8, 48, 88, 120, 124 and so on.
Challenge:
The mathematics in the question doesn't make sense1, so we can't find the correct answ... | [] |
Introduction:
We all know these three basic arithmetic math tables I assume.
ADDITION:
+ | 1 2 3 4 5 6 7 8 9 10
----------------------------------
1 | 2 3 4 5 6 7 8 9 10 11
2 | 3 4 5 6 7 8 9 10 11 12
3 | 4 5 6 7 8 9 10 11 12 13
4 | 5 6 7 8 9 10 11 12 13 14
5 | 6 7 8 9 10 11 ... | [] |
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