The runtime speed of the solution is a criterion of this challenge. "Faster, faster would be better."

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4
votes
3answers
153 views

Autoscale complex function

Context: We are working on a complex image drawing program to produce mugs, t-shirts, and so on. Here is an example of such function However, we are facing the following problem: Random generated ...
2
votes
2answers
139 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
349 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
125 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 ...
6
votes
7answers
749 views

Count the Zeros

For a given n, count the total number of zeros in the decimal representation of the positive integers less than or equal to n. For instance, there are 11 zeros in the decimal representations of the ...
3
votes
4answers
217 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
637 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 ...
2
votes
2answers
459 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 ...
5
votes
3answers
447 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
781 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 ...
2
votes
5answers
715 views

Challenge: take ciphered text and decipher, also print out if it was offset to the left or right [closed]

Problem: Take input text like this: (all input should be considered strings) Upi djpi;f ytu yu[omh pmr yp yjr ;rgy. And figure out if it was offset left or offset right (on a standard qwerty ...
5
votes
3answers
443 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, ...
5
votes
2answers
2k 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 ...
6
votes
6answers
549 views

Count the number of cyclic words in an input

Cyclic Words Problem Statement We can think of a cyclic word as a word written in a circle. To represent a cyclic word, we choose an arbitrary starting position and read the characters in ...
0
votes
4answers
438 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
707 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
166 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 ...
8
votes
2answers
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
238 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
308 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
628 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
619 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
399 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 ...
2
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
887 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 ...
-2
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
577 views

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

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
446 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 ...
35
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
430 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: ...
0
votes
1answer
503 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 _ ...
8
votes
12answers
2k views

Write the fastest Fibonacci

This is yet another challenge about the Fibonacci numbers. The goal is to compute the 20'000'000th Fibonacii number as fast as possible. The decimal output is about 4 MiB large; it starts with: ...
6
votes
3answers
1k views

Lottery Ball Problem

A woman works at a lottery ball factory. She's instructed to open up a lottery ball creation kit composed of 1 red rubber ball and n strips of digits from 0 through 9. She's instructed to do the ...
3
votes
13answers
2k views

Check if number is a sum of consecutive numbers or not

Write a program that checks if a given positive integer can be represented as sum of two or more consecutive positive integers. Example: 43 can be represented as 21 + 22 10 = 1+2+3+4 but 4 cannot ...
58
votes
23answers
7k views

Contest: 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 ...
11
votes
2answers
862 views

Fastest python code to find a set of winning words in this game

This is a word game from a set of activity cards for children. Below the rules is code to find the best triplet using /usr/share/dict/words. I thought it was an interesting optimization problem, and ...
5
votes
4answers
665 views

Code-Challenge:The Nearest Prime

Challenge In this task you would be given an integer N you have to output the nearest prime to the integer. If the number is prime itself output the number. The input N is given in a single ...
3
votes
4answers
501 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 is given in a single line,the inputs are ...
8
votes
2answers
557 views

Break the broken cipher

I have designed a simple random generator that cycles two numbers in a chaotic way using a multiply and modulus method. It works great for that. If I were to use it as a cipher generator it would ...
2
votes
4answers
1k views

Carmichael Numbers

EDIT: I am changing the challenge. 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. ...
13
votes
30answers
2k views

Implement division

Implement a division algorithm in your favourite language which handles integer division. It need only handle positive numbers - but bonus points if it handles negative and mixed-sign division, too. ...
6
votes
3answers
430 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 ...
5
votes
4answers
991 views

Fast line drawing algorithm

The task is to find a way to draw a horizontal line in an array of 16-bit integers. We're assuming a 256x192 pixel array with 16 pixels per word. A line is a contiguous run of set (1) bits. Lines ...