About DSA Tools

What this is

A family of interactive learning tools for data structures and algorithms courses, built by Reza Khojasteh for his students: the Time Complexity Playground (the course's 5-step Big-O derivation plus in-browser benchmarking), the Recursive Functions Visualizer (watch the call stack and call tree of your own recursive code), and the BT/BST Coding Assistant (AI-generated practice questions with hidden solutions). The tools assist your reasoning — they don't replace it.

Privacy, in one place

• No login, no accounts, no database — on any of the tools.
• Code you paste or write is analyzed and executed entirely in your browser (Python runs in a sandboxed WebAssembly worker); it is never sent to a server of ours.
• The one exception is explicit: the BT/BST Assistant (and the Playground's optional AI mode) sends your request to openrouter.ai using your own API key, only when you click, and remembers the key only if you opt in.
• Each tool's own About page has the full details for that tool.

Colophon

Open source, built as a Bun monorepo with Next.js, Tailwind, and shared workspace packages — the source lives at github.com/reza-khojasteh/dsa-tools.