Learn algorithms by watching them run.

Step through every comparison and swap — at your pace, on your numbers.

Data Structures

Picture an egg carton: a row of little cups, each numbered, each the same size.

6 lessons · concept

Think of a stack of plates by the sink.

Concept · coming soon

Picture the line at a coffee shop.

Concept · coming soon

Imagine a treasure hunt.

Concept · coming soon

Imagine kids lining up by height, but each kid can only compare with the neighbour directly beside them and swap places.

7 lessons

Think of finding a word in a dictionary.

3 lessons

The Singleton pattern makes sure there is only ever one of something — like the one TV remote a whole house shares.

Concept · coming soon

The Observer pattern lets one thing automatically ping a whole crowd the moment something changes — just like a YouTube channel alerting its fans.

Concept · coming soon

The Adapter pattern is the travel plug of code — a small piece that sits between two things that do not fit and lets them work together anyway.

Concept · coming soon

Think of a line of people who need to face the other way without leaving their spots empty.

4 lessons

Two sorted piles of exam papers need to become one.

3 lessons