1.1 Getting you started
To get started, we need to set up some very limited infrastructure.
Your programming environment
Choose a programming language and a code editor you are comfortable with. I'll mostly use python and Visual Studio Code, though I might write a handful of Java programs, too. Get familiar with the unix shell / terminal (e.g. bash); I'm talking about this:

We will run our programs from the terminal. I would suggest you don't use an IDE. We will only write small single-file programs, so an IDE will not be necessary.
The online judge
There are sites that have collected vast numbers of contest problems and also allow you to submit your solutions, where they will be tested against hidden test cases. A scoreboard will then show your statistics:

As of April 4, 2025, I have submitted a total of 1 (one) problem(s), having a success rate of 100%. This page will become more red over time, I guess.
Open an account on the sphere online judge. I might recommend other online judges as time passes.
Our judge at TU Chemnitz
We have set up our own non-public online judge at TU Chemnitz:
You have to be in the TU Chemnitz network or vpn to use it. You'll need a user account. Our TA Drashti Patel will set one up for you. We are still dealing with certain issues, so it does not work as of April 4, 2025.