Questions tagged [number]
A competition to solve a particular problem through the usage and manipulation of numbers.
1,179
questions
24
votes
19answers
3k views
Analog is Obtuse!
An analog clock has 2 hands*: Hour and minute.
These hands circle the clock's face as time goes by. Each full rotation of the minute hand results in 1/12th of a rotation of the hour hand. 2 full ...
8
votes
0answers
230 views
Fastest way to iterate over sublattice of discrete lattice
I need to construct a functor that iterates over the linear representation of a sub-lattice of size \$d_x,d_y,d_z,d_q\$ embedded in a lattice of size \$n_x,n_y,n_z,n_q\$. The sub-lattice corner is ...
14
votes
4answers
475 views
Distributing parliament seats
Introduction
In a general election, one would like to calculate a constant price per parliament seat. This means that for N >= 0 seats to be distributed and a ...
22
votes
6answers
1k views
Subtract the Folded Matrix
Challenge:
Given an NxN matrix where \$N\geq2\$ and one of eight distinct 'folding options', output a 2D array/list with the subtracted values.
The eight folding options are: left-to-right; right-to-...
13
votes
7answers
500 views
Print the total length of all "quoted" characters
Rules
In this challenge, I'm going to redefine the definition of "quotes" a bit.
Quotation marks (AKA quotes) are any identical characters used in pairs in various writing systems to set off direct ...
12
votes
6answers
977 views
Group Integers by Originality
Introduction:
I collect twisty puzzles. Most twisty puzzles are produced and sold by Chinese companies. Most well-known companies ask permission from puzzle designers to produce their designs and work ...
16
votes
34answers
2k views
Incremental Ranges!
Your task is to, given two positive integers, \$x\$ and \$n\$, return the first \$x\$ numbers in the incremental ranges sequence.
The incremental range sequence first generates a range from one to \$...
21
votes
23answers
3k views
Rotated Position of Integers
Challenge:
Input:
A sorted list of positive integers.
Output:
The amount of integers which are still at the exact same index, after rotating the digits in each integer its index amount of times ...
9
votes
4answers
636 views
Leading and Suffering Numbers
Introduction:
In Dutch, the words leading and suffering, being 'leiden' and 'lijden' respectively, are pronounced the same way. One is written with a "short ei", and one with a "long ij&...
36
votes
18answers
3k views
Count rotary dial pulses in a phone number (including letters)
In your grandparents' day, dialing a phone number was done with a rotary dial like this:
To dial each digit, put your finger in the corresponding hole, pull it over to the finger stop, and release it....
19
votes
24answers
2k views
To exponential digit growth and beyond!
Challenge
Given a base \$1 < b < 10\$ and an index \$t \ge 1\$, output term \$x_t\$, defined as follows:
\$x_1 = 11_{10}\$
\$x_{i+1}\$ is obtained by converting \$x_i\$ to base \$b\$ and then ...
-2
votes
11answers
367 views
Convert a number into "bracket" numerals
"Bracket" numerals are a type of 'numerals' I made up once, and thought would be a nice challenge here. Basically, you convert the input number into base 6, and then transliterate the ...
19
votes
15answers
2k views
Divisor Rich and Poor Numbers
Introduction
In the strange world of integer numbers, divisors are like assets and
they use to call "rich" the numbers having more divisors than their reversal, while they call "poor&...
21
votes
16answers
3k views
Cuban Primes
Given a natural number \$n\$, return the \$n\$-th cuban prime.
Cuban Primes
A cuban prime is a prime number of the form
$$p = \frac{x^3-y^3}{x-y}$$
where \$y>0\$ and \$x = 1+y\$ or \$x = 2+y\$
...
13
votes
12answers
475 views
Find all \$k\$-smooth pairs
Introduction
In number theory, we say a number is \$k\$-smooth when its prime factors are all at most \$k\$. For example, 2940 is 7-smooth because \$2940=2^2\cdot3\cdot5\cdot7^2\$.
Here, we define a \$...
30
votes
19answers
6k views
Is it a Munchausen Number?
A Munchausen Number in base \$b\$, also known as a Perfect digit-to-digit invariant or PDDI is a peculiar type of positive integer where the sum of its base-\$b\$ digits raised to themselves is equal ...
0
votes
3answers
205 views
Roots of Arbitrary Numbers [closed]
One day, when I was bored in maths class, I learned of a neat trick for solving the real cube root of a number!
Let's use the number \$79,507\$ as an example.
First, take digit in the one's place ...
13
votes
17answers
3k views
Convert Numbers To Emoji Math [closed]
In Emoji Math, a user created module for the video game Keep Talking And Nobody Explodes, numbers are written as strings of emoticons, where each emoticon represents a base 10 digit.
Below is the ...
17
votes
23answers
1k views
Enumerate Derangements
Given some positive integer \$n\$ generate all derangements of \$n\$ objects.
Details
A derangement is a permutation with no fixed point. (This means in every derangement number \$i\$ cannot be in ...
29
votes
23answers
4k views
32
votes
21answers
2k views
A Note on N!
J. E. Maxfield proved following theorem (see DOI: 10.2307/2688966):
If \$A\$ is any positive integer having \$m\$ digits, there exists a positive integer \$N\$ such that the first \$m\$ digits of \$N!...
23
votes
21answers
2k views
Maximum summed subsequences with non-adjacent items
Introduction:
Inspired by these two SO questions (no doubt from the same class): print the elements in the subarray of maximum sum without adjacent elements java and Maximum sum of non adjacent ...
35
votes
21answers
7k views
Amount of permutations on an NxNxN Rubik's Cube
Introduction:
A 3x3x3 Rubik's Cube has \$43,252,003,274,489,856,000\$ possible permutations, which is approximately 43 quintillion. You may have heard about this number before, but how is it actually ...
37
votes
7answers
3k views
List of Python versions
Python is the fastest-growing major programming language today. It is the most wanted language for the third year in a row, meaning that developers who do not yet use it say they want to learn it.[1]
...
11
votes
6answers
3k views
Area of a 2D convex hull
You are given an array/list/vector of pairs of integers representing cartesian coordinates \$(x, y)\$ of points on a 2D Euclidean plane; all coordinates are between \$−10^4\$ and \$10^4\$, duplicates ...
1
vote
0answers
158 views
How many right triangles can you find? [closed]
Challenge
You will be given an input represented by x, which is a string containing at least 3 characters. It will consist only of the standard numeric characters, ...
19
votes
15answers
3k views
Match Roman Numerals
Challenge
Given some input string, return a truthy value if it represents a correct roman numeral between 1 (=I) and 3999 (=...
49
votes
50answers
11k views
Patience, young "Padovan"
Everyone knows the Fibonacci sequence:
You take a square, attach an equal square to it, then repeatedly attach a square whose side length is equal to the largest side length of the resulting rectangle....
10
votes
3answers
758 views
How long does it take to type this?
Introduction
I can type at a moderate pace, using the QWERTY keyboard layout. But if a word like yellowwooddoor has a ton of repeated letters, it takes a bit longer to type it. Even worse is when a ...
10
votes
5answers
510 views
Valid term from quadratic sequence?
You are given four numbers. The first three are \$a\$, \$b\$, and \$c\$ respectively, for the sequence:
$$T_n=an^2+bn+c$$
You may take input of these four numbers in any way. The output should be ...
19
votes
15answers
1k views
Expand and Contract
Take a positive integer \$k\$ as input. Start with \$n := 1\$ and repeatedly increase \$n\$ by the largest integer power of ten \$i\$ such that \$i \le n\$ and \$i + n \le k\$.
Repeat until \$n = k\$ ...
27
votes
13answers
3k views
Valid Badminton Score?
Introduction:
I saw there was only one other badminton related challenge right now. Since I play badminton myself (for the past 13 years now), I figured I'd add some badminton-related challenges. Here ...
17
votes
26answers
901 views
Calculating total slots
Given a list of jobs, which must be done in order, with each taking a slot to do, how long will it take to perform them all if after doing a job the same job cannot be done for the next two slots (...
26
votes
22answers
2k views
The Digit Triangles
Challenge:
Input: A positive integer \$n\$
Output:
Create a list in the range \$[1,n]\$, and join it together to a string (i.e. \$n=13\$ would be the string ...
-1
votes
1answer
108 views
Sort a list of Numbers as letters [closed]
So, you have a random list (random meaning it doesn't matter what order it is in) of numbers with a length of n, where n is a positive integer smaller than 1000 and ...
35
votes
52answers
9k views
Am I not good enough for you?
Background:
The current Perfect Numbers challenge is rather flawed and complicated, since it asks you to output in a complex format involving the factors of the number. This is a purely decision-...
35
votes
27answers
8k views
Could you please stop shuffling the deck and play already?
Challenge:
Input: A list of distinct positive integers within the range \$[1, \text{list-size}]\$.
Output: An integer: the amount of times the list is riffle-shuffled. For a list, this means the list ...
12
votes
10answers
647 views
New Order #1: How does this feel?
Introduction
Putting all positive numbers in its regular order (1, 2, 3, ...) is a bit boring, isn't it? So here is a series of challenges around permutations (reshuffelings) of all positive numbers.
...
70
votes
48answers
7k views
Is it a Cyclops number? "Nobody" knows!
Task:
Given an integer input, figure out whether or not it is a Cyclops Number.
What is a Cyclops number, you may ask? Well, it's a number whose binary representation only has one ...
33
votes
25answers
5k views
The (Easy) Road to Code
Input:
An integer \$n\$, which is guaranteed to be \$\ge3\$.
An integer \$d\$, which is one of \$[-1,0,1]\$.
Output:
A road of size \$n\$, which will be in a north-west direction if \$d=-1\$; a ...
12
votes
31answers
2k views
Sum integers in a string [duplicate]
Input
A string.
Output
The sum of all integers in the line.
Constraints
1≤Length of line≤500
Sample test Case
Input
the 5is 108 seCONd4 a
Output
...
12
votes
18answers
2k views
Jumping Numbers
A jumping number is defined as a positive number n which all pairs of consecutive decimal digits differ by 1. Also, all single digit numbers are considered jumping numbers. eg. 3, 45676, 212 are ...
asked Mar 1 '19 at 17:11
Luis felipe De jesus Munoz
9,8092 gold badges22 silver badges78 bronze badges
35
votes
5answers
8k views
Historical difference between `/` and `÷` in mathematical expressions
Introduction:
Inspired by a discussion that is already going on for many years
regarding the expression \$6÷2(1+2)\$.
With the expression \$6÷2(1+2)\$, mathematicians will quickly see that ...
77
votes
39answers
12k views
Am I a Rude Number?
For a while now, I've been running into a problem when counting on my fingers, specifically, that I can only count to ten. My solution to that problem has been to count in binary on my fingers, ...
21
votes
17answers
2k views
Square Root Distance from Integers
Given a decimal number k, find the smallest integer n such that the square root of n is ...
19
votes
25answers
3k views
23
votes
17answers
4k views
The real treasure was the numbers we made along the way
Your task is to write a program, function or snippet (yes, snippets are allowed) that simply outputs an integer. However, you must be able to separate your submission into prefixes that also produce ...
46
votes
24answers
7k views
Covering a Skyline with brush strokes
Given a non-negative integer skyline height list, answer how many uninterrupted 1-unit-high horizontal brush strokes are needed to cover it.
[1,3,2,1,2,1,5,3,3,4,2]...
2
votes
7answers
369 views
Countries by Area
Challenge
Given two non negative integers a < b, output all countries, from the below Top 100 Countries, where area is between ...
5
votes
2answers
633 views
A Multipurpose Quine
I personally love quines, but they all seem to be so... static. So why not create a quine that can do more.
Challenge
The challenge here is to create a quine that without any sort of input is a ...
