Overview of several approaches to rank results by an average score provided by users, and why most fail to provide a satisfying solution. Concluding with a formula that yields better results.

Notes on how to programmatically generate fictional maps that look like something you’d find at the back of fantasy novels.

PROBLEM: You are a web programmer. You have users. Your users rate stuff on your site. You want to put the highest-rated stuff at the top and lowest-rated at the bottom. You need some sort of “score” to sort by.

We’re not living in an algorithmic culture so much as a computational theocracy.

List of ingenious algorithms in computer science

Efficiently querying geospatial data is a considerable challenge: because the data is two-dimensional (or sometimes, more), you can’t use standard indexing techniques to query on position. Spatial indexes solve this through a variety of techniques. This post covers several - quadtrees, geohashes, and space-filling curves - and reveal how they’re all interrelated.

Introduction to Ternary Search Tries

Notes on the following algorithms and methods:

• Levenshtein distance
• Damerau-Levenshtein distance
• Bitap algorithm with modifications by Wu and Manber
• Spell-checker method
• N-gram method
• Signature hashing method
• BK-trees

Mathematics-based programming problems

I hear algorithms-type questions come up a lot, so I would like to prepare really well as quickly as I can. What good sources would HN recommend?

Most people use this web site to get information about a particular number sequence. If you are a new visitor, then you might ask the database if it can recognize your favorite sequence, if you have one.