The "trick" to writing recursive code

Name: The "trick" to writing recursive code
Rating: 4.5 (1 reviews)

A short course presenting a trick to quickly and correctly implement recursive functions.

Created byAhmed Hisham

Last updated 2/2026

English

English [Auto],

What you'll learn

Learn to quickly and correctly write recursive functions
Acquire a simple mental check to test the completeness of recursive solutions/implementions
Tackle different classes of problems with the same trick
Conceptually understand recursive problem solving

Course content

2 sections • 16 lectures • 1h 56m total length

Introduction1:05
Ahmad explains a simple trick to overcome getting stuck implementing recursive solutions and helps students translate recursive ideas into working code.
A note before we begin2:52
Discover a simple trick to quickly implement recursive functions. The lecture emphasizes prerequisites from recursive thinking and the pyramid drawing problem to show why the approach works.
Recursive thinking: A Conceptual Walkthrough(Part 1: Intro)8:29
Learn to solve a left-aligned pyramid of stars using recursion by building a smaller pyramid and adding one row, illustrating problem decomposition into subproblems.
Recursive thinking: A Conceptual Walkthrough(Part 2: Problem Breakdown)8:17
Explore recursive thinking by breaking a four-level pyramid into sub-problems, solving a three-level pyramid, then adding a final row, illustrating dependence on the immediately previous solution.
Recursive thinking: A Conceptual Walkthrough(Part 3: Misconceptions)6:32
Explore recursive thinking by incrementally building a pyramid from a trivial one-level case, solving each sub-problem by adding a row, and avoiding the misconception that recursion stacks multiple separate pyramids.
Recursive thinking: A Conceptual Walkthrough(Part 4: The Main Idea)6:47
Learn to solve pyramid drawing through recursive thinking by deferring computation, establishing a base case, and building the full solution row by row from smaller sub-problems to any height.
Recursive thinking: A Conceptual Walkthrough(Part 5: The General Case)11:47
Explore recursive thinking by drawing a left-aligned star pyramid, using a one-level base case and decrementing by one to build any n-level pyramid.
Recursive thinking: A Conceptual Walkthrough(part 6: The Computational View)6:57
Explore the computational view of recursion, linking problem breakdown to executable steps and showing how the base case draws a star to build a pyramid.
The Pyramid Problem: Implementation(contains an important idea to the "trick")9:18
Define a recursive pyramid function with a base case of one level and a recursive step that draws an extra row of n stars after solving the n-1 level pyramid.
The Pyramid Problem: Execution Breakdown(+implementation completeness check)10:38
Explore a quick trick to write recursive functions by breaking down the pyramid problem’s execution from a one-level base case to an n-level pyramid, with a completeness check.
Before we continue(The recursive mindset)0:56
Understand why tracing the execution of a recursive function doesn't help you write recursive code, and adopt a logical, structure-first mindset for correct implementations.

The powerset problem[Explanation and recursive solution]17:06
Explore power set through a recursive solution, reducing the set by one element and including the excluded element to form all subsets, with the base case at the empty set.
Implementing the powerset function (+ the trick)5:45
Master recursive powerset construction by defining the empty set base case and using the pretend recursion trick to build all subsets by adding the last element.
Why does this trick work?6:43
Explore how mathematical induction justifies the recursion trick, showing that solving the base case guarantees the correctness of all smaller subproblems and subsequent recursive calls.
Towers of Hanoi / Fibonacci13:09
Explore recursive problem solving with Towers of Hanoi and Fibonacci, applying base cases and breaking problems into two smaller subproblems to generate correct move sequences and Fibonacci values.
Appendix A: Some "textbook" definitions0:30

Requirements

Basic familiarity with a programming language(Python will be used)
Extremely basic familiarity with the concept of recursion

Description

This course presents a quick and effective trick to ease the implementation of recursive functions. The main objective of the course is to specifically overcome the experience of getting "stuck" while writing recursive function. There are also conceptual lectures discussing general concepts related to recursion. The so-called trick is discussed and applied practically through problems, then justified logically. Recursion is one of the most important topics for a computer scientist or programmer to understand. Recursion is also a vital concept to grasp for the study of data structures and algorithms . Python is used for implementation. This course is not for absolute beginner programmers as assumes a basic familiarity with at least one programming language. Also, the student being introduced to the basic ideas of recusion is preferred. Python is used for implementation. This course is not for absolute beginner programmers as assumes a basic familiarity with at least one programming language. Also, the student being introduced to the basic ideas of recusion is preferred. Python is used for implementation. This course is not for absolute beginner programmers as assumes a basic familiarity with at least one programming language. Also, the student being introduced to the basic ideas behind recursion is preferred.

Who this course is for:

All programmers who struggle with recursion!

The "trick" to writing recursive code

What you'll learn

Explore related topics

Course content

Conceptual Prerequisites11 lectures • 1hr 14min

The "trick"5 lectures • 43min

Requirements

Description

Who this course is for: