Code by AI. Scalability by Engineers.
AI can generate code, but it can’t reason about long-term performance. Joona DSA helps engineers use DSA to identify inefficiencies and design systems that remain reliable and scalable over time.
Reverse a Linked List (Blindfolded)
Given the head of a singly linked list, reverse the list, and return the reversed list. Constraint: You cannot use `Array.reverse()`. Do not look at StackOverflow.
// ChatGPT won't save you here.
function reverseList(head) {
// Write your code here...
// If you switch to Claude, we'll know.
}
Features
Early Performance Risk Detection
Develop the ability to evaluate algorithmic complexity and identify performance risks before they impact production systems.
System Design Foundations
Strengthen your understanding of core data structures and algorithms that support maintainable, scalable, and well-architected systems.
AI Learning Helper
An intelligent assistant that explains complex algorithms and helps you debug code with real-time feedback.
Bring Your Own API Key
Use your own API key to generate practice problems on demand. No subscriptions, no data retention, and full control over your usage.
Progress Analytics
Track your submission history and success rate. Compare solutions with other anonymous users to learn different approaches.
Dual Language Support
Learn in your preferred language. All problems and documentation are fully translated between English and Indonesian.