Project Euler - Java Streams

My implementations of solutions for the problems in Project Euler, as I am coding it along.

Development Process & Reflections

This repository contains my personal solutions for the Project Euler challenges. My primary goal here is to explore modern Java features and adopt a functional programming style. I'm aiming for code that is elegant, concise, and expressive, though I recognize there is always room for optimization.

What I'm Focusing On (and Proud Of)

• Modern Java Capabilities: I'm making extensive use of recent Java features, such as Unnamed Classes and Instance Main Methods (void main()), as well as Records for immutable data. This keeps the boilerplate to a minimum.
• Functional Programming & Streams: I heavily favor the Stream API (IntStream, etc.) and Static Imports to keep the code declarative and readable. Sometimes this comes at a slight performance cost compared to imperative arrays, but expressiveness is my priority.
• Reusability: As I progress, I'm extracting common logic into generic utilities, like the PrimeToolKit for primes and a Memoizer for caching recursive results.
• Algorithmic Efficiency: I try my best to avoid pure brute force, favoring approaches like the Sieve of Eratosthenes or prime factorization to achieve better algorithmic complexity.

Room for Improvement

While I'm happy with how clean the codebase is, I know there are compromises:

• The Cost of Elegance: My caching strategy relies on wrappers (like Long). It's elegant and reusable, but I recognize that the constant boxing/unboxing overhead makes it slower than using primitive arrays if raw performance is the only goal.
• Awareness of Bottlenecks: In some problems, I've used recursive generators that allocate all possibilities in memory. I'm aware of more optimal mathematical approaches (like the Factorial Number System) and I leave notes for myself to refactor these bottlenecks in the future.
• Matrix Traversals: Matrix checks could be abstracted better with directional arrays (dx/dy) to avoid repetitive if statements, but for now, I value the straightforwardness of the current implementation.

Ultimately, this project is a learning journey—a balance between writing beautifully modern Java and solving complex mathematical problems efficiently.

To-Do

• Build a stream-efficient Prime number detection library
• Add a time efficiency calculating library