Contributions are always welcome. Language doesn't matter. Just make sure you're implementing an algorithm.
PRs are welcome. To begin developing, follow the structure:
If there is an implementation of the same algorithm in your language, do not give a PR for that.
Please include a description for the algorithm that you are implementing. It doesn't matter if it's copied from somewhere as long as it helps people that are learning new algorithm.
Graphical examples would be very helpful too.
You can include tests as well.
Don't remove previous implementations of algorithms. You can help in improving the current implementation by adding explanations and examples.
Beautify and clean up your code for easier reading
The curated list of resources dealing with algorithms.