If you are looking for a public repository to contribute. This is the place to be!
Contribute to Open source and make the world a better place. You can create new folders if you want to. But take special care while naming them. Programmers need not be descriptive but when it comes to being organised, hell yeah.
You can create your own issues.
Contributions are always welcome. Language doesn't matter. Just make sure you're implementing an algorithm.
Feel free to create a pull request. If it is not a spam, it will be accepted and sometimes merged.