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Questions tagged [math]

The challenge involves mathematics. Also consider using more specific tags: [number] [number-theory] [arithmetic] [combinatorics] [graph-theory] [geometry] [abstract-algebra].

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9
votes
1answer
443 views

The working time calculator

This is based on how my company deals with the monitoring of the working times for every employee. Each one of us has a card that can be passed in front of a sensor, so that a clock registers the ...
7
votes
1answer
239 views

Implement the Method of Finite Differences

The Method of Finite Differences is a technique used to find the next term in a sequence of numbers, given that the sequence is governed by consecutive values of a certain polynomial. Given a list of <...
6
votes
4answers
2k views

Calculate e^x and ln(x)

Given a floating point x (x<100), return e^x and ln(x)...
3
votes
13answers
2k views

Transpose a 3x3 matrix across the anti-diagonal

Write a program which takes a 3x3 matrix on stdin and prints its transpose along the anti-diagonal to stdout. You may assume that all elements of the matrix will be integers. Columns are space-...
3
votes
7answers
708 views

Resolve quadratic equation

Challenge: Write the smallest program (in characters) that resolves quadratic equations i.e. ax² + bx + c = 0 Rules: Given 3 numbers in R comma-delimited on ...
2
votes
1answer
176 views

Advent Challenge 7: Balance the storage carts!

<< Prev Next >> After some careful analysis, Santa was able to determine the dock size ranges and get the presents into the correct transportation dock. Now, he needs you to help him balance ...
0
votes
1answer
287 views

Calculate the a ^ b WITHOUT using *, / and ^ [duplicate]

Challenge Your goal is, given two positive integer numbers a and b, to calculate (and output) a ^ b without using either multiplication, division and the power itself (not directly, at least). And, ...
-6
votes
20answers
614 views

XOR reduction bools

Description : Given a string of space separated binary digits or space separated booleans or an array of binary digits or array of booleans . Your job is to find the xor of each until you end up with ...
91
votes
35answers
16k views

Mandelbrot image in every language

I always used a Mandelbrot image as the 'graphical' version of Hello World in any graphical application I got my hands on. Now it's your guys' turn. Language must be capable of graphical output or ...
121
votes
11answers
12k views

(-a) × (-a) = a × a

We all know that \$(-a) \times (-a) = a \times a\$ (hopefully), but can you prove it? Your task is to prove this fact using the ring axioms. What are the ring axioms? The ring axioms are a list of ...
175
votes
47answers
28k views

Mathematics is fact. Programming is not

In mathematics an exclamation mark ! often means factorial and it comes after the argument. In programming an exclamation mark !...
62
votes
9answers
5k views

How lit is this mountain? 🔥

A mountain is defined to be a set of line segments whose first point has coordinates (0,a) where a > 0, and whose last point ...
45
votes
19answers
9k views

Draw/plot a heart graph

Your challenge is to draw/plot one of the hearts below. The size must be at least 50x50 pixels (vector graphics is OK). You may choose which of the hearts you want to draw/plot. Axes, grid lines etc. ...
44
votes
4answers
2k views

Multiply with restricted operations

There's a 500 rep unofficial bounty for beating the current best answer. Goal Your goal is to multiply two numbers using only a very limited set of arithmetic operations and variable assignment. ...
48
votes
17answers
5k views

Knight on the Rim is Grim

Introduction Aron Nimzowitsch was a leading chess master and a influential chess writer. In his book 'My System', the first chapter deals about the importance of the center and why you should ...
57
votes
10answers
10k views

Little Chandler is sad. Draw him a cloud to cheer him up

Little Chandler is sad. Draw him a cloud to cheer him up. Note: Drawing a cloud won't actually cheer him up. A circle can be defined as a 3-tuple (x,y,r) where <...
50
votes
33answers
4k views

How many steps does it take from n to 1 by subtracting the greatest divisor?

Inspired by this question over at Mathematics. The Problem Let n be a natural number ≥ 2. Take the biggest divisor of ...
48
votes
65answers
10k views

Divide a number by 3 without using *, /, +, -, % operators

Quoting this question on SO (Spoiler alert!): This question has been asked in an Oracle interview. How would you divide a number by 3 without using *, /, +, -, %, operators? The number ...
43
votes
32answers
4k views

Define a function f such that f(f(n)) = -n for all non-zero integers n

This challenge was inspired by a programming blog I frequent. Please see the original post here: A Programming Puzzle Challenge Define a function f:Q->Q such ...
37
votes
5answers
1k views

Overcoming cluster size

Fed up with the reliability of flash storage, you decided to store all your programs on one of those good old 1,440 KiB floppies. However, after copying not even 3,000 programs, the disk was full. How'...
24
votes
59answers
4k views

Adding without using a + or - sign

There have been many "Do __ without __" challenges before, but I hope that this is one of the most challenging. The Challenge You are to write a program that takes two natural numbers (whole numbers ...
44
votes
38answers
9k views

Weapons of Math Instruction

Last time when I tried to come up with something easy that wasn't a duplicate, it ended up being way too hard.. So hopefully this time it's indeed something newcomers can try as well. Input: An ...
37
votes
59answers
3k views

Difference of the square of the sum

Find the difference between the square of the sums and sum of the squares. This is the mathematical representation: \$\left(\sum n\right)^2-\sum n^2\$ Your program/method should take two inputs, ...
21
votes
2answers
1k views

Integer Linear Programming

Introduction Write a solver for integer linear programming. Challenge Your task is write a solver for integer linear programming (ILP). In ILP, linear inequalities of a set of unknowns (all of ...
15
votes
7answers
2k views

Where should I put my restaurant?

You are the owner of a restaurant. You are opening in a new area in Cartesia where there is only one main road, known as the y-axis. You want to place your restaurant such that you minimize the total ...
28
votes
26answers
2k views

Fundamental Solution of the Pell Equation

Given some positive integer \$n\$ that is not a square, find the fundamental solution \$(x,y)\$ of the associated Pell equation $$x^2 - n\cdot y^2 = 1$$ Details The fundamental \$(x,y)\$ is a pair ...
24
votes
21answers
2k views

Approximate the plastic number

The challenge The plastic number is a number related to the golden ratio, with many interesting mathematical properties. As such, there are many approaches that can be used to calculate the number. ...
23
votes
11answers
3k views

Bijective function ℤ → ℤⁿ

It is trivially possible to create a bijective function from \$\mathbb{Z}\$ (the set of all integers) to \$\mathbb{Z}\$ (e.g. the identity function). It is also possible to create a bijective ...
16
votes
6answers
6k views

Count number of hefty decimals between 2 numbers

Let's say we have a non-negative integer that is "hefty" (that is, "heavy") if its average digit value is greater than 7. The number 6959 is "hefty" because: (6 + 9 + 5 + 9) / 4 = 7.5 The number ...
48
votes
44answers
5k views

Detect heat waves

Background The Royal Netherlands Meteorological Institute defines a heat wave* as a series of at least 5 consecutive days of ≥25°C weather (“summery weather”), such that at least 3 of ...
44
votes
26answers
6k views

How does math work in Anastasiya's world?

Background: Standard operation math like basic addition and multiplication in the real world work like these: 12 + 123 = 135 and ...
36
votes
18answers
5k views

Automate your first grade counting exercise

CodeGolf Challenge PWSSHHHH! You wake up in a cryogenics lab in the year 3000. Upon being escorted to the assignment office to receive your career chip, presumably that of a delivery boy, a probe ...
36
votes
21answers
7k views

Angle between the hands on a clock [duplicate]

Given the time in 24 hour format (2359 = 11:59pm) return the angle between the minute and hour hands on a standard clock (on the ...
31
votes
10answers
1k views

Find the dot product of Rationals

I was at a friend's house for dinner and they suggested the idea of a "Prime-factor vector space". In this space the positive integers are expressed as a vector such that the nth element in the ...
29
votes
2answers
899 views

Addition on Elliptic Curves

Addition on Elliptic Curves Disclaimer: This does not do any justice on the rich topic of elliptic curves. It is simplified a lot. As elliptic curves recently got a lot of media attention in the ...
28
votes
11answers
2k views

Find the largest gap between good primes

Following the fine tradition of questions such as Find the largest prime whose length, sum and product is prime , this is a variant on a largest prime challenge. Input Your code should not take any ...
25
votes
15answers
2k views

Linear Regression on a String

This challenge is a little tricky, but rather simple, given a string s: meta.codegolf.stackexchange.com Use the position of ...
24
votes
61answers
6k views

Golf the xᵗʰ root of x

While bored in high-school (when I was half my current age...), I found that f(x) = x(x-1) had some interesting properties, including e.g. that the maximum f for 0 ≤ x is f(e), and that the binding ...
23
votes
0answers
557 views

Maximal discrepancy-2 sequence with minimal entropy

Background As noted in the PPCG challenge Compress a maximal discrepancy-2 sequence – which inspired this challenge – the authors of the paper Computer-Aided Proof of Erdős Discrepancy Properties ...
20
votes
9answers
2k views

Is it within the Cantor set?

The Challenge For this challenge, you are supposed to determine if a given number is in the Cantor set. So first, let's define the Cantor set. First, start with the numbers between 0 and 1. Any ...
19
votes
26answers
3k views

Calculate Standard Deviation

Challenge Given a list of numbers, calculate the population standard deviation of the list. Use the following equation to calculate population standard deviation: Input The input will a list of ...
18
votes
28answers
1k views

Calculate the inverse modulus

The task: Output a value for x, where a mod x = b for two given values a,b. Assumption <...
14
votes
41answers
3k views

Minimum excluded number

This is intended to be an easy, bite-size code-golf. The mex (minimal excluded number) of a finite collection of numbers is the smallest non-negative integer ...
14
votes
4answers
2k views

It’s time to do the math

Introduction This is one of my favorite math puzzles. Given a digit (say 3) and the number of times to use that digit (say 5), generate 10 expressions which result to 1, 2, 3, 4, 5, 6, 7, 8, 9 and ...
11
votes
3answers
975 views

Matrix property X revisited (or the Joy of X)

This challenge is partly an algorithms challenge, partly an optimization challenge and partly simply a fastest code challenge. A T matrix is fully specified by its first row ...
47
votes
39answers
5k views

The Snail in the Well

Background There's a common riddle that goes something like this: A snail is at the bottom of a 30 foot well. Every day the snail is able to climb up 3 feet. At night when they sleep, they slide ...
44
votes
37answers
5k views

If A-B be in A-B A else B eh?

Given two integers, A and B, output A if A-B (A minus B) is in A-B (A to B), otherwise output B. "A minus B" is standard subtraction. "A to B" is the range of integers starting at A and ending at B, ...
43
votes
37answers
6k views

Calculate the difficulty of a Code Golf question

Briefing The difficulty of a Code Golf question can be calculated as such: Where v is the number of views a question has and a...
41
votes
33answers
3k views

Goodness Giza Golf!

A "Giza number", also colloquially known as a Timmy Number is any number where the digits represent a pyramid (A134810). For example, "12321" is a giza number because it can be visualized like this: <...
38
votes
51answers
6k views

Don't give me five!

Question : You will be given the starting and ending integers of a sequence and should return the number of integers within it which do not contain the digit 5. ...