Questions tagged [fastest-code]

The winner of a fastest-code challenge is determined by the runtime performance of the submissions. For fairness, all submissions should be benchmarked on the same machine, which usually means all submissions have to be tested by the host of the challenge. For scoring by asymptotic time complexity, use [fastest-algorithm] instead.

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6 votes
3 answers
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Generate Fibonacci Primes Quickly

Unsurprisingly, fibonacci primes are primes that are also Fibonacci numbers. There are currently 34 known Fibonacci primes and an additional 15 probable Fibonacci primes. For the purpose of this ...
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  • 2,155
5 votes
1 answer
1k views

fastest matrix multiplication on x86

This challenge requires integration with C, so you can stop reading if you're not interested. Matrix multiplication is a simple operation, but the performance depends a lot on how efficiently the code ...
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  • 2,213
1 vote
1 answer
404 views

Best performance on x/(y+z) + y/(x+z) + z/(x+y) = N

Consider the equation $$\frac x {y+z} + \frac y {x+z} + \frac z {x+y} = n$$ for positive integers \$x, y, z\$ and \$n \ge 4\$. Your code will receive \$n\$ as an input, and output three integers \$x, ...
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10 votes
2 answers
505 views

The maximum liberty of a group on a Go board

Bounty One of the convincing conjectures, by Loopy Walt is, ...
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  • 2,213
23 votes
12 answers
2k views

Quicksand (piles)

In this fastest-code challenge, you take a positive integer as input, which represents the height of a sand pile, located at (0,0) on an infinite square grid. For example, if our input is ...
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  • 6,705
11 votes
6 answers
894 views

High throughput prime numbers

This challenge is inspired by the High throughput Fizz Buzz challenge. The goal Generate a list of prime numbers up to 10,000,000,000,000,000. The output of primes should be in decimal digits followed ...
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  • 2,213
6 votes
2 answers
464 views

Write the most optimized assembly program to detect a prime number (from a bigger range!)

This is the second version of the task. The original task had a defect that the given range of integers was too small. This was pointed out by @harold that other methods couldn't defeat the way of ...
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  • 2,213
2 votes
1 answer
829 views

An Scalable Event Scheduler That Can Handle Billions of Events [closed]

The event scheduler is a recurrent theme in event-driven architectures: something triggers an event that needs to be checked in the future one or more times. I has particular use in trading where you ...
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6 votes
1 answer
536 views

Fast Matrix Multiplicator Evaluator

A triplet of real tensors \$(A,B,C)\$ of size \$\gamma \times \gamma \times \sigma\$ represents a matrix multiplication algorithm with \$\sigma\$ elementary multiplications iff the following function ...
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  • 69
6 votes
2 answers
664 views

Bigram frequencies in text

Introduction This challenge is about producing a code to count the frequency of bigrams in a text. A bigram is two consecutive letters in a text. For instance 'aabbcd' contains the bigrams aa, ab, bb, ...
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7 votes
1 answer
481 views

Compute the size of intersections of sets

Input A positive integer N representing the size of the problem and four positive integers v, x, y, z. Output This is what your code should compute. Consider a set of N distinct integers and consider ...
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6 votes
3 answers
377 views

Swap encoding iteration count

Introduction In this challenge, I asked you to implement swap encoding. Swap encoding is an encoding method where you iterate through the string, reversing substrings between identical characters. The ...
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6 votes
3 answers
388 views

Fastest unique finder

Given 4096 16-bit integers, only four of which are unique and others appeared twice (so 2050 different integers exist). Find the four uniques. To time precisely and limit RAM usage, your program will ...
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  • 12.8k
15 votes
2 answers
391 views

Connecting the Dots: Counting n²-gons in the n×n Grid

The recent volume of MAA's Mathematics Magazine had an article "Connecting the Dots: Maximal Polygons on a Square Grid" by Sam Chow, Ayla Gafni, and Paul Gafni about making (very convex) \$n^...
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  • 8,107
20 votes
12 answers
3k views

Fastest draw in the west! [closed]

We're going rootin' tootin' cow-poke shootin! This is a simple contest, first program to draw their pistol wins. How it works: I require 2 things from you, an executable, and a command to be run from ...
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  • 3,583
-1 votes
1 answer
177 views

Print all digits of an integer [duplicate]

Challenge Given a positive integer, find the fastest way to iterate over its digits. Bytecode size doesn't matter as much as speed of execution. Examples For 6875, the program would output ...
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8 votes
3 answers
383 views

Patterns in Permutations

This fastest-code challenge is based partly on this MSE question and exists to extend some OEIS sequences, and create others. If I extend or create sequences based on this challenge, I'll link to this ...
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  • 8,107
5 votes
1 answer
327 views

2D Pathfinding with Momentum

You are piloting a spaceship, outfitted with an engine that can accelerate you at 1km/s^2 in the direction the ship is facing (you have very good inertial dampers). You also have thrusters which can ...
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  • 2,005
40 votes
0 answers
1k views

Topologically distinct ways of dissecting a square into rectangles

I was asked by OEIS contributor Andrew Howroyd to post a Code Golf Challenge to extend OEIS sequence A049021. Would be super great to get a couple more terms for [...] A049021. Kind of thing [...] ...
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  • 8,107
2 votes
0 answers
237 views

Compute the Three Dimensional Discrete Cosine Transform

Challenge I've checked that there is a question Compute the Discrete Cosine Transform which is a competition for implementing a shortest solution to compute the one dimensional discrete cosine ...
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  • 403
8 votes
4 answers
1k views

Compute all close strings quickly

Input A string S of length between 10 and 16 inclusive. The characters are taken from the 95 printable ASCII characters, byte values 32 (...
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284 votes
33 answers
193k views

High throughput Fizz Buzz

Fizz Buzz is a common challenge given during interviews. The challenge goes something like this: Write a program that prints the numbers from 1 to n. If a number is divisible by 3, write Fizz instead....
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12 votes
7 answers
2k views

Fastest square root of an arbitrary size

We do seem to have a fastest square root challenge, but it's very restrictive. In this challenge, your program (or function) will be given an arbitrarily sized nonnegative integer, which is the square ...
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-6 votes
1 answer
165 views

No. Of Factors Does the Number Have [duplicate]

Create a function which takes in a input integer and then returns the number of factors it has, like if you pass 25 then it will return ...
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  • 157
3 votes
0 answers
168 views

Sums of permutations of vectors [closed]

I am looking for a more efficient way of computing the following. Let A and B be two vectors of non-negative integers of length <...
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2 votes
1 answer
322 views

Crazy Blazin' DOM Injection

Introduction This problem is a challenge that has to do with DOM manipulation at scale and overcoming some issues that may be inherent in dealing with the DOM. This challenge is interesting because ...
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9 votes
3 answers
504 views

Number of tilings on a triangular board with triangular tiles

Background Consider the shape \$T(n)\$ consisting of a triangular array of \$\frac{n(n+1)}{2}\$ unit regular hexagons: John Conway proved that \$n = 12k + 0,2,9,11\$ if and only if \$T(n)\$ can be ...
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  • 62.8k
11 votes
3 answers
517 views

Triangles in a tetrahedron

The goal of this challenge is to extend the OEIS sequence A334581. Number of ways to choose \$3\$ points that form an equilateral triangle from the \$\binom{n+2}{3}\$ points in a regular tetrahedral ...
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  • 8,107
10 votes
1 answer
532 views

How quickly can you convert an NFA to a DFA?

Convert NFA to DFA as quickly as possible. Input Your input will be an NFA. In order to be able to test your code, it needs to be able to handle an NFA in the following format. This is taken ...
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5 votes
0 answers
331 views

Hamming distance traveling salesman problem

The Hamming distance between two strings is the number of positions they differ at. You are given a set of binary strings. The task is to find the length of the shortest route that visits all of them ...
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  • 8,246
19 votes
1 answer
648 views

Acyclic orientations of an n-dimensional cube

The goal of this challenge is to check and extend the OEIS sequence A334248: Number of distinct acyclic orientations of the edges of an n-dimensional cube. Take an n-dimensional cube (if n=1, this is ...
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  • 199
11 votes
2 answers
408 views

Spanning paths in a tournament on n nodes

The goal of this challenge is to extend the On-Line Encyclopedia of Integer Sequences (OEIS) sequence A038375. Maximal number of spanning paths in tournament on n nodes. A tournament on \$n\$ ...
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  • 8,107
15 votes
6 answers
742 views

Calculate the average longest common substring exactly

[Question inspired by Can you calculate the average Levenshtein distance exactly? . Thank you Anush. ] The longest common substring between two strings is the longest substring which is common to ...
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3 votes
3 answers
349 views

Generate A298757 [closed]

Miller-Rabin test Given a base \$b\$ and an odd number \$n\$: Write \$n\$ as \$2^{s}\times d + 1\$ where \$d\$ is odd \$n\$ is a strong probable prime if either: \$b^d\equiv 1 \pmod n\$ \$b^{d\cdot2^...
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34 votes
19 answers
8k views

Fastest yes in the west

There has been a question about yes in the past, but this one is slightly different. You see, despite yes having a rather long size, it is incredibly fast. Running ...
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27 votes
4 answers
889 views

Buildings made from cubes

In this fastest-code challenge, you are provided with a set of \$n\$ identical blocks and need to determine how many unique buildings can be constructed with them. Buildings must satisfy the following ...
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  • 16.6k
5 votes
1 answer
588 views

Average number of strings with Levenshtein distance up to 4

This is a version of this question which should not have such a straightforward solution and so should be more of an interesting coding challenge. It seems, for example, very likely there is no easy ...
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13 votes
4 answers
2k views

Can you calculate the average Levenshtein distance exactly?

The Levenshtein distance between two strings is the minimum number of single character insertions, deletions, or substitutions to convert one string into the other one. The challenge is to compute ...
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22 votes
2 answers
782 views

Find the number of n-by-n (-1, 0, 1) matrices with zero permanent as quickly as possible

The permanent of an \$n\$-by-\$n\$ matrix \$A = (a_{i,j})\$ is defined as: $$\operatorname{perm}(A)=\sum_{\sigma\in S_n}\prod_{i=1}^n a_{i,\sigma(i)}$$ For a fixed \$n\$, consider the \$n\$-by-\$n\$ ...
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  • 665
-1 votes
1 answer
144 views

Symbol Search Deleter [rephrased] [closed]

Your challenge is to parse nonsensical text and output a "congruous phrase" - which I shall define here to be text with any contiguous characters in between, and including, a given set of like symbols ...
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  • 21
-5 votes
2 answers
379 views

Fastest N times Hello World (Java/C/ C++) [closed]

Not a new one: Input N, being n, 0 ≤ n ≤ 5. Output N times "Hello World." Example: Input 3 Output Hello World. Hello World. Hello World. These 2 are my ...
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8 votes
1 answer
680 views

Compute OEIS A161169, approximately and quickly

\$T(n, k)\$ gives the number of permutations of length \$n\$ with up to \$k\$ inversions. This values grows very quickly, for example for \$T(20, 100) = 1551417550117463564\$. The maximum number of ...
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5 votes
1 answer
379 views

Find minimal set of rows to retain all unique values in each column

Given a matrix, the goal is to ensure all the values in each column occur at least once, while at the same time doing so requiring the least possible amount of rows. Fastest solution wins. Note: a ...
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34 votes
12 answers
13k views

The fastest Sudoku solver

Winner found It seems as if we have a winner! Unless anyone plans on contesting the world's current fastest Sudoku solver, user 53x15 wins with the staggeringly fast solver Tdoku. For anyone still ...
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  • 6,667
38 votes
18 answers
7k views

Bentley's coding challenge: k most frequent words

This is perhaps one of the classical coding challenges that got some resonance in 1986, when columnist Jon Bentley asked Donald Knuth to write a program that would find k most frequent words in a file....
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6 votes
1 answer
479 views

Multiplication in Brainfuck - minimum number of evaluations [closed]

Given two numbers in tape location #0 and tape location #1 in Brainfuck, compute their product into another tape location (specify with answer). Optimize for the least amount of time-units used, where ...
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9 votes
0 answers
246 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 ...
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6 votes
2 answers
871 views

Check if all vowels exist in pairs of strings [closed]

Your program should find the number of string pairs (pairs of 2) that contain all vowels (a e i o u), when given an integer N and ...
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  • 173
27 votes
6 answers
2k views

Prime containment numbers (speed edition)

This is sequence A054261 The \$n\$th prime containment number is the lowest number which contains the first \$n\$ prime numbers as substrings. For example, the number \$235\$ is the lowest number ...
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  • 6,667
11 votes
3 answers
521 views

Arbitrary Randomness (Speed edition)

Given integer n, calculate a set of n random unique integers in range 1..n^2 (inclusive) ...
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  • 11.2k