# Algorithms

*## 1 What's an algorithm?

An algorithm is simply a series of logical instructions that show, from start to finish, how to accomplish a task. By this broad definition, a cake recipe counts as an algorithm.

Usually, algorithms refer to something a little more specific. They still boil down to a list of step-by-step instructions, but these algorithms are almost always mathematical objects.

## 2 Types of algorithm

There's no overall consensus on how to group algorithms, but you can think of four main categories (Hello World):

- prioritization (making an ordered list)
- classification (picking a category)
- association (finding links)
- filtering (isolating what's important)

Most algorithms are some combination of the above.

## 3 Algorithmic approaches

You can think of the approaches taken by algorithms as broadly fitting into two key paradigms.