Welcome to the Foundation Course

This course teaches the basic data structures you need to know before diving into our core algorithm content. You'll learn how computers store data, what arrays and linked lists are, and the fundamental structures like stacks, queues, and hash tables that appear everywhere in programming. It is useful both for new programmers and for experienced engineers who want a structured refresh before interview-focused algorithm patterns.

What You'll Learn

The Foundation Course covers nine essential modules that build on each other:

Module 1 - Computer Basics: How computers store data in memory, what happens when you create variables, and why understanding memory matters for writing good code.

Module 2 - Understanding Speed: How to measure if code is fast or slow using Big O notation, and why some operations take constant time while others grow with input size.

Module 3 - Arrays: The most fundamental data structure - storing elements in contiguous memory for fast access by index.

Module 4 - Strings: How text is stored and manipulated, from basic operations like concatenation to pattern matching and transformations.

Module 5 - Linked Lists: Dynamic data structures where elements are scattered in memory but connected through pointers, enabling efficient insertions and deletions.

Module 6 - Queue: First-In-First-Out (FIFO) data structures used everywhere from task scheduling to breadth-first search.

Module 7 - Hash Tables & Sets: Fast lookup structures that turn O(n) searches into O(1) operations using clever hashing techniques.

Module 8 - Stack: Last-In-First-Out (LIFO) data structures powering function calls, undo operations, and depth-first algorithms.

Module 9 - Sorting: Basic sorting algorithms, built-in sort functions, custom comparators, and common sorting applications.

Who This Course Is For

This course is designed for two groups: people who just learned to program, and experienced engineers who can code but have not recently practiced interview-style data structures. If you can write basic loops and functions in any programming language, you're ready to start. No computer science background required.

How to Use This Course

Each module follows the same pattern:

1. Learn the concept - Articles explain what each data structure is, how it works, and why it matters
2. See it in code - Examples in 9 languages (Python, Java, JavaScript, TypeScript, C++, C#, Go, Rust, Ruby) show how to use it
3. Practice problems - Apply what you learned with guided exercises and solutions

Work through the modules in order. Later modules build on concepts from earlier ones. If you are brushing up for interviews, timebox each practice problem: struggle long enough to learn the idea, then read the explanation, understand the solution, and keep moving. The Core Patterns Course will revisit these ideas in more interview-specific forms.

Let's begin with Module 1: Computer Basics.