Setup
Examples use Python because it reads like pseudocode — but every concept transfers to any language. If you finished the Python track's setup you're ready. Otherwise install Python and run examples in a file or the REPL.
Lessons
1
Big-O: Measuring Speed
Before learning any data structure, you need the vocabulary for comparing them. …
→
2
Arrays & Strings
The array is the simplest data structure: items in a row, side by side in memory…
→
3
Hash Maps & Sets
The hash map is the most useful data structure in programming: look anything up …
→
4
Stacks, Queues & Linked Lists
Three structures about controlling the ORDER things come out: stacks (last in, f…
→
5
Recursion
A recursive function calls itself on a smaller piece of the problem until the pi…
→
6
Trees & Binary Search
A tree is nodes and pointers arranged as a hierarchy: one root, branching childr…
→
7
Graphs: BFS & DFS
A graph is nodes plus edges connecting them — no hierarchy required, cycles allo…
→
8
Sorting: How & When
Sorting is the most-studied problem in computer science, and the ideas inside th…
→
9
DSA Cheatsheet
Every structure, its costs, and when to reach for it — one page.
→