Show HN: I couldn't afford interview prep, so I built a free alternative

A developer created a free platform for preparing for big tech company coding interviews, featuring structured lessons on data structures and algorithms, interactive visualizations, a Python code editor that runs in the browser, and AI-powered feedback. The platform covers 16 topics organized as a skill tree with prerequisites, allowing users to progress through concepts like arrays, linked lists, dynamic programming, and system design without requiring a signup.