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.

Filter by
Sorted by
Tagged with
293 votes
34 answers
214k 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....
14 votes
8 answers
2k views

Filter a large file quickly

The challenge is to filter a large file quickly. Input: Each line has three space separated positive integers. Output: All input lines A ...
35 votes
19 answers
9k 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 ...
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 [...] ...
34 votes
12 answers
14k 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 ...
6 votes
2 answers
393 views

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 ...
13 votes
2 answers
677 views

Write a FAST word equation solver

This question is similar to Write a word equation solver by David Frank but different in three important ways: (1) David asked for just the first solution found, and I am asking for all the solutions. ...
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 ...
11 votes
6 answers
925 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 ...
1 vote
1 answer
421 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, ...
10 votes
2 answers
508 views

The maximum liberty of a group on a Go board

Bounty One of the convincing conjectures, by Loopy Walt is, ...
8 votes
2 answers
525 views

Filter a large file in small memory

The challenge is a follow-up to Filter a large file quickly which had two submissions where were as fast as wc! This time the difficulty is that RAM is severely restricted which means that new ...
7 votes
4 answers
4k views

Carmichael Numbers

Write a program to print Carmichael numbers. The challenge is to print the maximum number of them in less than 5 secs. The numbers should be in increasing order. Please do not use built in functions. ...
1 vote
13 answers
1k views

position of the only 1 in a number in binary format [closed]

Every number of the form 2i (where i is a non-negative integer) has a single 1 in its binary representation. Given such a number, output the 1-based position of the ...
38 votes
18 answers
8k 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....
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 ...
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 ...
71 votes
23 answers
12k views

Fastest way to sort a big array of Gaussian-distributed data

Following the interest in this question, I thought it would be interesting to make answers a bit more objective and quantitative by proposing a contest. The idea is simple: I have generated a binary ...
2 votes
9 answers
7k views

compute number of 1 bits in a binary representation of a number

The goal is to write a program that returns number of 1 bits in a given number. Examples 5 -> 2 1254 -> 6 56465 -> 8 Winner The winning ...
2 votes
1 answer
852 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 ...
19 votes
1 answer
649 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 ...
6 votes
2 answers
474 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 ...
20 votes
3 answers
22k views

Fastest code to find the next prime

The problem is as follows. Input: An integer n Output: The smallest prime bigger than n. The challenge is to give the ...
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 ...
6 votes
2 answers
685 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, ...
73 votes
15 answers
14k views

Calculate the number of primes up to n

π(n) is the number of primes less than or equal to n. Input: a natural number, n. Output: π(n). Scoring: This is a fastest-code challenge. Score will be the sum of times for the score cases. I ...
22 votes
2 answers
785 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\$ ...
10 votes
1 answer
536 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 ...
7 votes
1 answer
482 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 ...
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^...
6 votes
3 answers
379 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 ...
37 votes
4 answers
17k views

Fastest semiprime factorization [closed]

Write a program to factorize a semi-prime number in the shortest amount of time. For testing purposes, use this: \$38!+1\$ (\$523022617466601111760007224100074291200000001\$) It is equal to: \$...
7 votes
3 answers
393 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 ...
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 ...
19 votes
6 answers
1k views

Fastest tweetable integer factorizer

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 ...
-1 votes
1 answer
178 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 ...
5 votes
1 answer
328 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 ...
8 votes
3 answers
388 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 ...
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 ...
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 (...
6 votes
1 answer
2k views

Sudoku board generator [closed]

A program that randomly generates a Sudoku game board with varying degrees of difficulty (however you decide to measure difficulty). Sudoku requires that there is only one solution, so your program ...
4 votes
3 answers
2k views

Fastest python implementation of multiplication table

I'd be interested to see who can come up with the fastest function to produce multiplication tables, in the following format: ...
3 votes
1 answer
842 views

Box Blur Challenge

The challenge is to implement a box blur in any language. The input will be as a 32-bit uncompressed bitmap, BGRA, preceded by one byte defining the radius of the blur and one byte defining the width ...
3 votes
1 answer
515 views

Fastest alphabetical list sort given the following limitations:

Your function must have an input that takes in an array containing 10000 random names, and must sort these names in alphabetical order. Names have a random length of up to 128 characters. ISO/IEC 8859-...
8 votes
5 answers
1k views

Code-Challenge: Farey sequence (II)

Challenge In this task you would be given an integer N (less than 10^6), output the number of terms in the Farey sequence of order N. The input N < 106 is given in a single line, the inputs ...
10 votes
1 answer
912 views

Count arrays that are really unique

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 ...
11 votes
3 answers
522 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 ...
8 votes
18 answers
1k views

Square-free semiprime counting

Definition A square-free semiprime is a natural number that is the product of two distinct prime numbers. The task Given a natural number n, count all square-free ...
14 votes
5 answers
753 views

Fast Topswops calculation

From AZSPCS: Suppose you have a deck containing n cards. Each card contains a number from 1 to n, and each number appears on exactly one card. You look at the number on the top card -- let's says it'...
-6 votes
1 answer
166 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 ...