code-challenges

Weekly(?) code challenges for the community to complete for learning and fun.

Submitting an Entry

If you'd like to submit a solution to a challenge you'll do so by creating an instance of CodeChallengeEntry which specifies your name and a code block to run with your solution in it.

Every challenge will have an implementation of CodeChallengeType which defines the InputType and OutputType that your solution block will need to take/return. This CodeChallengeType implementation should also include comments in it that describe the challenge itself, so it is your one-stop shop for figuring out what you need to do to successfully complete the challenge.

Here's step-by-step instructions on how to get an entry submitted:

1. Fork the repo and clone it to your machine
2. Open the Xcode project and navigate to the CodeChallenge -> Challenges folder of the Challenge you'd like to submit an entry for.
3. Create a new file to put your solution in. Typically it should be named yourUsername-challengeNameEntry.swift.
4. In that file instantiate a CodeChallengeEntry object into a global named using the following format:

let usernameChallengeNameEntry = CodeChallengeEntry<ChallengeNameChallenge>(name: "username") {  input in
  // Your implementation here, returning the appropriate `OutputType`
}

5. Navigate to the ChallengeNameChallenge.swift file and add the global instance you created to the Challenge's entries array.
6. To test your implementation and see how it compares to any previously submitted solutions just run the tests (⌘+U)!
7. Once you're happy with your results commit and push your changes to your fork and submit a Pull-Request back upstream.

Some notes on etiquette

Given that everybody's submissions all run in the same module and namespace it's good to take a few things into account while writing your solution:

• It's a great idea to have additional functions or data structures to use in your implementation but please, if you do, mark them private so that they don't pollute the global namespace.
• Don't print anything. These will probably get flagged when you submit your PR, but save us a step and just don't commit 'em (or use custom breakpoints to do the trick ;) )! Currently we use the debug console from the test runs to output the results of the challenge runs, so the less console noise the better.

If you're just wanting to submit entries to an existing challenge, you're done! The rest of this README is for folks wanting to create new challenges, if that's you... read on!

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Submitting a new Challenge

In order to submit a new challenge you'll need to create an implementation of CodeChallengeType. This protocol defines:

• The input and output types for the entries' block property
• A title for the challenge
• The Array of entries that will be run (you just have to make an empty array of the appropriate type: [CodeChallengeEntry<YourCodeChallenge>])
• A function to generate the dataset which is just an array of InputTypes which will be fed to each entry over multiple iterations to run the challenge.
• A function to verify the output of the entry for a given input.

Your implementation should be named using the following format: FooChallenge for a Challenge named Foo. You should also include the description of the challenge as comments in this implementation file.

This Challenge implementation should be created in a subfolder of the Challenges directory and, in this case, the subfolder would be named Foo and the file would be FooChallenge.swift.

Check out CodeChallenge/Base/ExampleCodeChallenge.swift for a very simple challenge, or the TwoSum challenge for a bit more involved example.

Last step is you'll need to add a test file for this challenge. The test mostly writes itself. Just create a new test in CodeChallengeTests/Challenges/FooTests.swift which will look approximately like this:

@testable import CodeChallenge

class FooTests: CodeChallengeTestCase {
    func testFooEntries() {
        runTestsForChallenge(FooChallenge())
    }
}

That's it! Submit a PR and watch everyone toil over your challenge!