The winner of fastest-code challenge is determined by the runtime performance of the submissions. For scoring by asymptotic time complexity, use [tag:fastest-algorithm] instead. "Faster, faster would be better."

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0answers
173 views

Faster average error

Introduction This is a spin-off of the excellent contest to convert an image to a predefined palette of another image. I analyzed the top answer, which is brilliant, but rather not efficient, and ...
5
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2answers
577 views

The distance between circles

Imagine you are given two lists of numbers which are to be interpreted as points on a circle of circumference 1000. Let us say circleA = [10, 24, 44, 175, 321, 579, 618, 841, 871, 979] circleB = ...
7
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2answers
298 views

2nd byte bias of RC4

Short version RC4, designed in 1987, is one of the most famous stream ciphers. This question asks you to practically demonstrate its 2nd byte bias (for a theoretical proof, see section 3.2 of this ...
7
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1answer
415 views

'Number' Crunching Benchmark

I just want to do some benchmarking of different programming languages. So here is a tip: You can use as many characters as you want. In the end there is only the time your program needed. So, here ...
2
votes
0answers
103 views

Write program which finds shortest expression for number [duplicate]

Write program which finds shortest expression for big integer. Expression may consist of + - * / ^ ! ( ) operations. ! stands for factorial, ^ - exponentiation, / - rational division. Number itself ...
4
votes
0answers
249 views

Write a FAST word equation solver [duplicate]

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. ...
3
votes
1answer
987 views

Optimal Minesweeper on the Largest Board

Overview: Your challenge is to write a program that will play minesweeper optimally, giving the best move in any position. Moreover, you must do this on the largest board possible. Game details: ...
4
votes
2answers
617 views

Longest mathematical expression in a grid

Given a grid which contains these signs: 0..9, x, =, write the fastest code that outputs the longest string of connected (horizontally, vertically, and diagonally adjacent), distinct cells which is a ...
0
votes
1answer
187 views

Find the fastest swim relay (shortest path of unique nodes and types)

fastest relay time = lowest possible total integer value of (a freestyle swimmers time) + (1 breastroke swimmers time) + (another backstroke swimmers time) + (another butterfly swimmers time) Each ...
1
vote
2answers
443 views

Find nth root of variable without using math operators/functions

Write a program which, given two positive integers n and x, will display the n-th root of x (which is also x1/n) in decimal to an accuracy of 0.00001. The program must output the resulting number in ...
12
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3answers
2k 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 n as input which specifies the size of the board. Starting ...
11
votes
6answers
1k 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, ...
6
votes
3answers
1k views

Super fast sampling from a tricky random distribution

This is a micro-optimization challenge. The task is to sample from the maximally skewed stable distribution F(x;1,-1,Pi/2,0). See Table 1 of http://arxiv.org/pdf/0908.3961v2.pdf . It is easiest to ...
5
votes
2answers
343 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 ...
5
votes
7answers
684 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 ...
7
votes
16answers
1k views

How much can you quickly multiply?

With the recent python bashing , here's an attempt to show python's strengths. Your challenge is to write a program that calculates the factorial of as high a number n as possible within 10 seconds. ...
10
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8answers
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 B, Tthat satisfy either of the following criterion. ...
19
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10answers
4k 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 ...
35
votes
13answers
10k 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 ...
105
votes
19answers
50k views

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

I have this code which I have written in python/numpy from __future__ import division import numpy as np import itertools n=6 iters = 1000 firstzero = 0 bothzero = 0 """ The next line iterates over ...
2
votes
2answers
157 views

Merging text files based on a prefix key

Imagine an ordered file set : file1, file2, ... fileN. Each file is a textual file that is made of lines that have the same format : A concatenation of a fixed-size key (the same among all the file ...
4
votes
2answers
405 views

Analysing the most common words in a text, and replacing them with a single byte

This is a very crude text encoding algorithm I came up with the other day. It won't work if the text has more than 256 different characters in it – but it does support Unicode, at least in my Python ...
-5
votes
3answers
144 views

Making “Code runner” [closed]

The task is to execute functions stored in a database, preferably xml. For example a function containing system.out.println("a"); is stored in a file code.xml and has been extracted as a string, how ...
0
votes
4answers
256 views

Creating a catalogue index

You have a program which creates an index for a catalogue. The last step is missing: it must find and consolidate page ranges within the list of pages for each entry. Each entry is currently an ...
7
votes
7answers
711 views

Enumerate all number that are palindromic in at least two of base 2, 8, 10, 16 or 64

Multi palindromic numbers Finding all number for which at least two** representation are palindromic, with more than one** characters, if in decimal, octal, hexadecimal, binary or in base64. ** have ...
4
votes
2answers
663 views

Fastest modular exponentiation

The challenge is to write code in any open source, available on linux, language of your choice to perform modular exponentiation. The input will be two randomly chosen 2048 bit positive integers ...
7
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3answers
507 views

Quickly divide in Manufactoria

Background Manufactoria has been marketed as a game, but we code-golfers can see it for what it really is: a two-dimensional programming language. The Manufactoria programming language is based ...
17
votes
2answers
844 views

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

Consider an expression 2^2^...^2 with n operators ^. Operator ^ means exponentiation ("to the power of"). Assume that it has no default assosiativity, so the expression needs to be fully parenthesized ...
5
votes
3answers
510 views

The making of “Spot It!”: Finding almost unique sets

Puzzle: Find a deck of c cards, each containing p pictures, such that no two pictures match on a given card, and exactly 1 picture on each card matches exactly 1 picture on each of the other cards, ...
6
votes
3answers
3k 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 fastest code possible to do this. I will test the code on values starting at ...
0
votes
4answers
481 views

Race to a Million

This falls under the Code puzzles the best. Fastest way to render the numbers 1-million in a web browser. Preferably using PHP, but use what you must. Numbers must be more than one on a line in the ...
8
votes
3answers
1k 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), ...
3
votes
3answers
779 views

Secret Santa Challenge [duplicate]

Possible Duplicate: Holiday Gift Exchange Background: Secret Santa is a Western Christmas tradition in which members of a group or community are randomly assigned a person to whom they ...
2
votes
1answer
205 views

Bob's Financial Planning (Maximize)

Bob's Financial Planning Bob lives in Pecunia. It is a small island city completely governed by the Pecunia City Council (PCC). PCC has decided to encourage foreign investments in the city by waiving ...
9
votes
3answers
2k views

Fastest semiprime factorization

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: ...
2
votes
2answers
278 views

given prime factors of a number, what is the fastest way to calculate it's proper divisors? [closed]

Given prime factors of a number, what is the fastest way to calculate divisors? clc; clear; sms=0; count = 1; x=0; for i=11:28123 fac = factor(i); sm = 1; for j = 1:length(fac)-1 ...
2
votes
2answers
337 views

List ALL prime-factorized natural numbers in ANY order

This is a variant of List prime-factorized natural numbers up to N in ascending order, but the solutions can be very different. Write a program that outputs prime factorizations of all natural ...
3
votes
2answers
767 views

List prime-factorized natural numbers up to N in ascending order

For a given n list prime factorization of all natural numbers between 1 and n in ascending order. For example, for n = 10 the output would be: 1: 2: 2^1 3: 3^1 4: 2^2 5: 5^1 6: 2^1 3^1 7: 7^1 8: 2^3 ...
2
votes
2answers
685 views

Help johnny to solve this Puzzle

Scenario Little Johnny wants to play with his friends today. But his babysitter won't let him go! After a lot of begging, the heartless nanny gives him her brand new electronic puzzle and says: "If ...
0
votes
3answers
450 views

Prime tester + nth-prime finder (TO BE CLOSED) [duplicate]

Possible Duplicate: List of first n prime numbers most efficiently and in shortest code This is to be closed soon - please don't answer (mod- please close!) This challenge is to write the ...
3
votes
9answers
2k views

Triangle Puzzle

Triangle Puzzle Consider the triangle below. This triangle would be represented by the following input file.    5   9 6  4 6 8 0 7 1 5 By starting at the top and ...
5
votes
1answer
1k views

Sudoku board generator

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 ...
5
votes
12answers
4k views

Random sampling without replacement

Create a function that will output a set of distinct random numbers drawn from a range. The order of the elements in the set is unimportant (they can even be sorted), but it must be possible for the ...
8
votes
5answers
1k 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 ...
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votes
5answers
2k 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 goal the winner is the code which runs in minimum time ...
-6
votes
5answers
731 views

write a code the find n-th number of Gray Code list [closed]

Write a function that, given N >= 0, finds the Nth number in a standard Gray code. Example input: 1 2 3 4 Example output: 1 3 2 6 Additional reference
2
votes
11answers
468 views

position of the only 1 in a number in binary format

Given N is a number from this list : 1, 2, 4, 8, 16, .... 2^i as you know there is only a single "1" in binary representation of above numbers. Question : write a code to find out the position of ...
37
votes
3answers
2k views

Help Indiana Jones to get the treasure

Story Indiana Jones was exploring a cave where a precious treasure is located. Suddenly, an earthquake was happen. When the earthquake was ended, he noticed that some rocks fell from the ceiling ...
2
votes
2answers
517 views

Fastest C/C++ comparison function for an opaque field containing doubles

Description: Write the fastest comparison function for an opaque field containing a double. Here is my example: // Three-way comparison function: // if a < b: negative result // if a > b: ...
1
vote
1answer
550 views

Write a Program to Solve the Secret Code

There is a secret code, 12 characters in length. Each character can be either a number or a letter. Every two hours, a random character in the secret code is revealed. For example: Hour 2: _ _ Q _ ...