The runtime speed of the solution is a criterion of this challenge. "Faster, faster would be better."
2
votes
5answers
338 views
Challenge: take ciphered text and decipher, also print out if it was offset to the left or right
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 ...
3
votes
3answers
333 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, ...
3
votes
2answers
533 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 ...
5
votes
6answers
396 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
403 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 ...
5
votes
3answers
495 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
401 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
140 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 ...
5
votes
2answers
658 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
1answer
344 views
tic-tac-toe data structure design challenge [closed]
Design a data structure such that getWinner method runs in O(1) time.
Assume you call put(x, y, Player) for each move.
Best space efficient solution wins.
2
votes
2answers
180 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
...
1
vote
2answers
221 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 ...
2
votes
2answers
256 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
410 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
289 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
923 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
2k 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 ...
6
votes
4answers
598 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 ...
-3
votes
5answers
637 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
401 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
1
vote
5answers
282 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 ...
30
votes
2answers
1k 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
339 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
419 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
11answers
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:
...
3
votes
13answers
1k 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 ...
55
votes
23answers
6k 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
621 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 ...
4
votes
4answers
475 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
380 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 ...
7
votes
2answers
472 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
687 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. ...
6
votes
3answers
401 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 ...
4
votes
4answers
872 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 ...
