Links to favorite tutorials on algorithms

These are a collection of favorite tutorials I've read relating to algorithms. These mostly use pseudocode and are not specific to a particular language. Some may have examples in a particular language, but rest assured the main explanation of the algorithm is given in a way where no particular language is needed.

I've collected these here as a reference guide in case I ever need to come back to them. I hope they might be useful for someone else too.

Manacher's Algorithm - used for finding the longest palindromic string in a sequence.

Bitwise comparisons - this article is about Lisp operators, but don't let that stop you! The bitwise comparison section has one of the best and most concise explanations I've seen. If you don't understand bitwise comparisons (in any language), it will all become clear after you read the explanation, even if you don't know Lisp.

Faces of Fibonacci - An absolutely superb explanation of the "How Many Ways to do x?" question. Highly recommended.

"Output the answer modulo 10^9+7" - A great description of not just why, but how, to calculate your answers modulo 10^9+7 - something that is frequently required in programming contests for problems when you're dealing with very large numbers. The article includes a very important explanation of why division is much more difficult to handle, and how to handle it if you need to.

And more to come soon!

How to center images horizontally using Grav

I've been playing around a bit with Grav. I was posing the question to myself: for the relatively simple use-cases I'm dealing with, could it possibly work for my purposes as an alternative to ProcessWire? The problem I was initially dismayed to find that Grav uses Markdown as its editor, which does not offer native support for horizontal centering of anything (text or images). However, Grav offers some tweaks that help make it easier to do specific things you might commonly want to do. I tried writing a sample article, and I found that one of the hardest things to do was to center an image horizontally. And horizontal centering of images is something I would typically do in most of the articles I would write. So the lack of easy horizontal centering is a highly significant drawback IMHO (most people do want to center images in an article!) However, this issue is made up for by other things in Grav: the relative speed, ease and flexibility of custom theming and built-in suppor

Life using the Linux operating system exclusively for the last few years

Above: my Linux desktop layout. Back in 2017, I switched my operating system entirely to Linux. In case anyone is wondering, here is what I experienced over the last few years. Others I interact with have no idea I'm on Linux. For example, if someone emails me an MS Word document that I need to complete, I simply open it with LibreOffice (an open-source word processing program that is pre-installed on most Linux systems), edit the document as needed - which is very easy since the same sorts of functionalities are available in LibreOffice - and then I can save it in MS Word format and email it back. Likewise, if I'm on a Zoom call, everything works just the way it does on PC and Mac. Zoom makes their application available for Linux too, I downloaded it and let it self-install, and it works exactly the same way as it does on other operating systems. I can point-and-click my way to whatever I need to do on Linux; no special knowledge required. If you want to dig deeper into script

Correct usage of unwind-protect and with-open-file in Lisp

Learning to use unwind-protect in Lisp typically crops up very early on when you're first learning the language. In fact, anything to do with I/O is going to be something you'll need to know early on. Yet unfortunately, I find that unwind-protect is not explained sufficiently well for a beginner to understand not just how to use it correctly, but why and when . Grappling with this myself, I found that hands-down the best explanation came from this YouTube video from Baggers: Luckily, in the case of file handlers, LISP already assumes you'll want to open a file with unwind-protect, so it provides the with-open-file macro for this exact purpose. It closes the file handler for you with a built-in unwind-protect. This is an advantage over manually opening and closing your file handlers, because if your program opens the file but never gets to the part with the close command (for example due to a run-time error in between those stages), the built-in unwind-protect make

Code Notelets

Search This Blog