Sha256: ff326d3fd432c4b6b0d1c7cdd00a9cb47a1a99f2409b84f9ae4d25b4b8a38535
Contents?: true
Size: 1.93 KB
Versions: 99
Compression:
Stored size: 1.93 KB
Contents
# Sieve Use the Sieve of Eratosthenes to find all the primes from 2 up to a given number. The Sieve of Eratosthenes is a simple, ancient algorithm for finding all prime numbers up to any given limit. It does so by iteratively marking as composite (i.e. not prime) the multiples of each prime, starting with the multiples of 2. Create your range, starting at two and continuing up to and including the given limit. (i.e. [2, limit]) The algorithm consists of repeating the following over and over: - take the next available unmarked number in your list (it is prime) - mark all the multiples of that number (they are not prime) Repeat until you have processed each number in your range. When the algorithm terminates, all the numbers in the list that have not been marked are prime. The wikipedia article has a useful graphic that explains the algorithm: https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes Notice that this is a very specific algorithm, and the tests don't check that you've implemented the algorithm, only that you've come up with the correct list of primes. ## Setup There are two different methods of getting set up to run the tests with Objective-C: - Create an Xcode project with a test target which will run the tests. - Use the ruby gem `objc` as a test runner utility. Both are described in more detail here: http://exercism.io/languages/objective-c ### Submitting Exercises When submitting an exercise, make sure your solution file is in the same directory as the test code. For example, if you're submitting `Bob.m` for the Bob exercise, the submit command would be something like `exercism submit <path_to_exercism_dir>/objective-c/bob/Bob.m`. ## Source Sieve of Eratosthenes at Wikipedia [http://en.wikipedia.org/wiki/Sieve_of_Eratosthenes](http://en.wikipedia.org/wiki/Sieve_of_Eratosthenes) ## Submitting Incomplete Solutions It's possible to submit an incomplete solution so you can see how others have completed the exercise.
Version data entries
99 entries across 99 versions & 1 rubygems