These days, I spend most of my time studying about databases and their internal architectures. I have been intrigued by the engineering behind such systems, such that I have been following the database course from CMU
Data Structures and Algorithms
As a web developer, It is not common for me to extensively use data structure and algorithms in the job. Most code are already provided by the language or the runtime such that you don’t have to reimplement everything from scratch. We already use the programming languages with garbage collectors, where it manages memory for you, so you also don’t have to take care of the