Coding Competition

Data Structures & Algorithms

CSCI 4513

Week 6, Lecture 11

Today's Learning Objectives

🎯 Understand recursion fundamentals
🎯 Practice recursive problem-solving
🎯 Compete in a friendly coding challenge
🎯 OR catch up on previous homework

What is Recursion?

Recursion is when a function calls itself to solve smaller versions of the same problem.

Classic Example: Factorial

function factorial(n) {
  // Base case
  if (n === 1) return 1;

  // Recursive case
  return n * factorial(n - 1);
}

factorial(5); // 120

Key Components:

Base Case: When to stop
Recursive Case: Call itself with simpler input
Progress: Each call moves toward base case

Why Learn Recursion?

📚 Essential for computer science fundamentals
🌳 Perfect for tree and graph traversal
🧩 Natural fit for divide-and-conquer algorithms
💼 Common in technical interviews
🧠 Develops algorithmic thinking skills

💡 Fun Fact: Many problems that seem complex iteratively become elegant when solved recursively!

Today's Format: Choose Your Path

🏆 Option A: Competition

Solve recursion exercises
Compete for prizes!
Test your skills
Learn from challenges

🔧 Option B: Lab Time

Catch up on homework
Get help with projects
Ask questions
No pressure!

Both options are equally valid! Choose what serves your learning best right now.

The Recursion Exercises

Today's challenges come from The Odin Project's Computer Science section:

github.com/TheOdinProject/javascript-exercises/tree/main/computer_science/recursion

Five Challenges:

Fibonacci: Generate Fibonacci sequence
Merge Sort: Sort array using divide-and-conquer
Linked List: Recursive list operations
Binary Search Tree: Build and traverse BST
Knight Travails: Find shortest path for chess knight

Competition Rules

How It Works:

🔗 Clone the repository from GitHub
⏱️ Work on the exercises during class
✅ Pass the automated tests
🏆 Prizes for top performers!

Important Guidelines:

You can use any resources (documentation, notes, etc.)
Work individually—this tests YOUR skills
Ask me for help if you're stuck
Focus on learning, not just winning!

Tips for Success

Start Simple: Begin with the easier exercises (Fibonacci)
Identify Base Cases: When should recursion stop?
Think Small: What's the simplest version of this problem?
Trust the Recursion: Assume your function works for smaller inputs
Use Console Logs: Track what's happening at each recursive call
Draw It Out: Visualize the recursion tree on paper
Test Incrementally: Run tests frequently to catch errors early

Let's Get Started!

Competition Track:

Clone the repository
Navigate to the recursion folder
Read the README for each exercise
Start coding!
Run tests: npm test

Lab Track:

Work on any incomplete homework assignments. Ask questions. Use this time to catch up and solidify your understanding!

A Note About The Odin Project Curriculum

We are largely skipping this section of The Odin Project:

A Bit of Computer Science

Why Skip It?

📚 You'll cover these topics in other CS courses
⏰ We need to focus on web development skills
🎯 Today's competition gives you a taste of recursion

💡 But Don't Ignore It Completely!

When you have time, work through these exercises on your own. They make excellent portfolio items and great practice for technical interviews. The data structures and algorithms here are fundamental CS knowledge!

Today's Takeaways

What You Accomplished:

✅ Learned recursion fundamentals
✅ Practiced recursive problem-solving
✅ Competed in coding challenges (or caught up on homework!)
✅ Developed algorithmic thinking skills

📅 Next Class: Intermediate Git

🏆 Competition Winners: TBD—great job everyone!