"Here are a couple of additional articles for this level:"
This lesson will be slightly different from the rest. It will differ in that it is only indirectly related to Java. That said, this topic is very important for every programmer. We're going to talk about algorithms.
In programming, there are a huge number of different data structures, and they too are not associated with a specific language. But you definitely need to know them. When solving specific problems, very often the most important thing is to choose the most suitable data structure for the problem.