How to use the assistant

1. Get an OpenRouter key

Create a free account at openrouter.ai and make an API key. Paste it into the key field — it goes only to openrouter.ai when you generate, and is remembered only if you opt in. Free models work without buying credits.

2. Pick a question type and model

Choose one of the four types — iterative or recursive, binary tree or binary search tree — to match what you want to drill. The model picker lists free models first and stronger paid ones below; if the list fails to load, type any OpenRouter model id.

3. Generate, solve, then reveal

Generate a question and try to solve it on paper or in your editor beforepressing "Show solution" — the two walkthroughs are designed so the first one clarifies the problem without spoiling the approach. Generate another question when you are done; the assistant steers the model away from your last few questions.

Study tips

• BST solutions should follow a single path down the tree in O(log n) — if a generated BST solution visits every node, treat it as a red flag and generate a fresh question.
• Iterative questions must use loops, recursive ones must use recursive calls — check the solution honors this before trusting it.
• Questions are AI-generated: read them critically, and see About & privacy for what that means.