Introduction to algorithms

Welcome to our introduction to algorithms. Here we’ll briefly sum up what algorithms are and try and explain why they are important. This page will hopefully provide you with a solid understanding of what an algorithm is, and how to spot real-world algorithms.


What is an algorithm?

An algorithm is a series of steps that, when followed in order, will achieve a particular task. An algorithm is commonly thought to be computing related, and while algorithms are used extensively in computing, they are certainly not restricted to that field.

For instance, a sorting algorithm can help you organize information, but a recipe can help you create a meal.

A recipe is a very useful way of visualizing an algorithm because it contains an input, in the form of ingredients, an output, in the form of the finished meal, and has a method or series of steps that must be followed in a particular order to turn the input into the output.


An algorithm must meet certain criteria for it to be a good algorithm. These are:

  • Definiteness – Each step must be clearly defined and easy to replicate.
  • Finiteness – There should be no infinite loops in an algorithm. It should have a finite amount of steps and terminate when complete.
  • Effectiveness – It must be possible to complete the algorithm with existing computing technology. It must also effectively produce the desired results consistently.


A very good video introduction to algorithms can be seen below: