All the problems that I've either completed, tried but didn't get the correct answer, or was interested in, but haven't attempted yet.
Most problems are in Java and are marked with custom annotations for completeness, with a reference to the original source and/or as interview questions.
The remaining problems are in Python or C.
All Java problems follow Kattis' Java runtime: Java 11; however, LeetCode uses Java 17 while HR uses 8.