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. Alternatively, the submission can be compared to a reference program. For scoring by asymptotic time complexity, use [fastest-algorithm] instead.

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340 votes
42 answers
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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....
Omer Tuchfeld's user avatar
154 votes
21 answers
112k views

How slow is Python really? (Or how fast is your language?)

I have this code which I have written in Python/NumPy ...
user avatar
74 votes
16 answers
15k 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 ...
Liam's user avatar
  • 3,215
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 ...
static_rtti's user avatar
54 votes
14 answers
20k views

How Slow Is Python Really (Part II)?

This is a follow up to How slow is Python really? (Or how fast is your language?). It turns out it was a bit too easy to get a x100 speedup for my last question. For those who have enjoyed the ...
user avatar
53 votes
4 answers
2k views

Extending OEIS: Counting Diamond Tilings

I promise, this will be my last challenge about diamong tilings (for a while, anyway). On the bright side, this challenge doesn't have anything to do with ASCII art, and is not a code golf either, so ...
Martin Ender's user avatar
45 votes
3 answers
4k views

Help Indiana Jones to get the treasure

Story Indiana Jones was exploring a cave where a precious treasure is located. Suddenly, an earthquake happened. When the earthquake ended, he noticed that some rocks that had fallen from the ...
JiminP's user avatar
  • 3,472
41 votes
0 answers
2k 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 [...] ...
Peter Kagey's user avatar
  • 8,679
39 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....
Andriy Makukha's user avatar
37 votes
12 answers
6k views

Find the largest prime whose length, sum and product is prime

The number 113 is the first prime whose length 3 is prime, digital sum 5 = 1 + 1 + 3 is ...
Calvin's Hobbies's user avatar
37 votes
4 answers
18k 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: \$...
Soham Chowdhury's user avatar
36 votes
19 answers
10k 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 ...
Asad-ullah Khan's user avatar
36 votes
12 answers
18k 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 ...
maxb's user avatar
  • 6,897
35 votes
11 answers
8k views

How high can you go? (A coding+algorithms challenge)

Now that everyone has developed their (often amazing) low level coding expertise for How slow is Python really? (Or how fast is your language?) and How Slow Is Python Really (Part II)? it is time for ...
user avatar
30 votes
9 answers
6k views

Calculate the permanent as quickly as possible

The challenge is to write the fastest code possible for computing the permanent of a matrix. The permanent of an n-by-n matrix ...
user avatar
28 votes
3 answers
1k views

Delete some bits and count

Consider all 2^n different binary strings of length n and assume n > 2. You are allowed ...
user avatar
27 votes
2 answers
3k views

Fastest Mini-Flak Quine

Mini-Flak is a subset of the Brain-Flak language, where the <>, <...> and [] ...
Wheat Wizard's user avatar
  • 98.7k
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 ...
maxb's user avatar
  • 6,897
27 votes
4 answers
988 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 ...
Nick Kennedy's user avatar
  • 21.1k
26 votes
3 answers
2k views

Approximating a special case of the Riemann Theta function

This challenge is to write fast code that can perform a computationally difficult infinite sum. Input An n by n matrix ...
user avatar
24 votes
2 answers
2k views

Compute the maximum number of runs possible for as large a string as possible

[This question is a follow up to Compute the runs of a string ] A period p of a string w is any positive integer ...
user avatar
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 ...
AnttiP's user avatar
  • 7,878
23 votes
4 answers
3k views

The Missing Number Revised

Background: I originally posted this question last night, and received backlash on its vagueness. I have since consulted many personnel concerning not only the wording of the problem, but also its ...
TheProgrammer's user avatar
23 votes
6 answers
1k views

Fastest Home Prime Generator

What is a home prime? For an example, take HP(4). First, find the prime factors. The prime factors of 4 (in numerical order from least to greatest, always) are 2, 2. Take those factors as a literal ...
Noah L's user avatar
  • 861
22 votes
9 answers
2k views

Build an Electrical Grid

The Challenge There are N cities aligned in a straight line. The i-th city is located A[i] kilometers to the right of the origin. No two cities will be in the same ...
Colera Su's user avatar
  • 2,421
22 votes
3 answers
851 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\$ ...
matrix42's user avatar
  • 665
22 votes
8 answers
1k views

Products that equal a sum and vice versa

A fun pair of equivalences is 1 + 5 = 2 · 3 and 1 · 5 = 2 + 3. There are many like these, another one is 1 + 1 + 8 = 1 · 2 · 5 and 1 · 1 · 8 = 1 + 2 + 5. In ...
orlp's user avatar
  • 39.1k
21 votes
4 answers
23k 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 ...
user avatar
21 votes
7 answers
1k views

How many sorting networks?

Below on the left is a picture of a sorting network that can sort 4 inputs. On the right you can see it sorting the input 3,2,4,1. A sorting network of size ...
AnttiP's user avatar
  • 7,878
21 votes
2 answers
590 views

Forming Polyominoes with a Chain of Rods

Background Consider a (closed) chain of rods, each of which has integer length. How many distinct hole-free polyominoes can you form with a given chain? Or in other words, how many different non-self-...
Martin Ender's user avatar
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 ...
tuskiomi's user avatar
  • 3,831
20 votes
9 answers
21k views

Super speedy totient function

The goal is simple: calculate the totient function for as many numbers as you can in 10 seconds and sum the numbers. You must print your result at the end and you must actually calculate it. No ...
qwr's user avatar
  • 12.1k
20 votes
7 answers
3k views

The smallest area of a convex grid polygon

I got an email from Hugo Pfoertner, an Editor-in-Chief at the On-Line Encyclopedia of Integer Sequences, with a terrific idea for a fastest-code challenge, which will also help verify or expand the ...
Peter Kagey's user avatar
  • 8,679
20 votes
4 answers
710 views

Plant trees in a park - As fast as you can!

This challenge is inspired by this app. The test cases are borrowed from that app. This is a fastest-code challenge, where the objective is to solve the largest test cases in the least amount of time....
Stewie Griffin's user avatar
20 votes
2 answers
1k views

The number of possible numeric outcomes of parenthesizations of 2^2^...^2

Consider an expression 2^2^...^2 with n operators ^. Operator ...
Vladimir Reshetnikov's user avatar
20 votes
1 answer
761 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 ...
mscroggs's user avatar
  • 309
19 votes
12 answers
4k views

Sum of smallest prime factors

SF(n) is a function which computes the smallest prime factor for a given number n. We'll call T(N) the sum of every SF(n) with 2 <= n <= N. T(1) = 0 (the sum is over 0 summands) T(2) = 2 (2 ...
Nicolás Siplis's user avatar
19 votes
7 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 ...
user avatar
19 votes
13 answers
877 views

As many near-repdigit primes as possible

A near-repdigit number is a positive integer where all the digits are the same, except one. For example 101 and 227 are near-repdigits. A near-repdigit prime is a near-repdigit that is also prime. For ...
user avatar
18 votes
3 answers
955 views

Finding all-but-one matches

This challenge is about writing code to solve the following problem. Given two strings A and B, your code should output the start and end indices of a substring of A with the following properties. ...
user avatar
17 votes
3 answers
4k views

Longest non-repeating Game-of-Life sequence

Given a positive integer N, determine the starting pattern on a N x N-grid that yield the longest non-repeating sequence under Game of Life-rules, and ends with a fixed pattern (cycle of length 1), ...
Per Alexandersson's user avatar
17 votes
3 answers
8k views

Fastest player for Dots and Boxes

The challenge is to write a solver for the classic pencil and paper game Dots and Boxes . Your code should take two integers m and ...
user avatar
17 votes
5 answers
4k views

Fast Trig Calculation

Fast Trigonometry Calculations Your task is to create a program which can calculate the sine, cosine and tangent of an angle in degrees. Rules No built-in trigonometry functions (not even secant, ...
user avatar
16 votes
3 answers
754 views

Find all the Solutions to this Number Puzzle in the Shortest Time Possible

History My company sends out a weekly newsletter to everyone within the company. Included in these newsletters is a riddle, along with a shoutout to whomever in the company was the first to email/...
Xirema's user avatar
  • 299
16 votes
2 answers
423 views

Permutations such that no k+2 points fall on any polynomial of degree k

Description Let a permutation of the integers {1, 2, ..., n} be called minimally interpolable if no set of k+2 points (together ...
Peter Kagey's user avatar
  • 8,679
15 votes
5 answers
3k views

Fastest Sort in BrainF***

After having implemented QuickSort in BrainF***, I realized it probably wasn't that quick. Operations that are O(1) in normal languages (like array indexing) are significantly longer in BF. Most of ...
AShelly's user avatar
  • 4,661
15 votes
6 answers
792 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 ...
user avatar
15 votes
5 answers
833 views

Compute the chromatic number of special graphs

This challenge is about computing the chromatic number of special types of graphs. Input The input will consist of two integers. A positive integer \$n > 1\$. A distance \$d < n\$. Task The ...
Simd's user avatar
  • 2,896
15 votes
2 answers
424 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^...
Peter Kagey's user avatar
  • 8,679
14 votes
12 answers
1k views

Finding approximate correlations

Consider a binary string S of length n. Indexing from 1, we can compute the Hamming ...
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