Generate Prefix-Based Product Suggestions

Problem

Given distinct lowercase product names and a lowercase search word, return suggestions after each typed character. For every non-empty prefix, return up to three lexicographically smallest products that start with that prefix.

Function Contract

Implement suggested_products(products, search_word) -> list[list[str]].

Constraints

• 1 <= len(products) <= 50000 and each product length is between 1 and 100.
• 1 <= len(search_word) <= 100.
• All strings contain only lowercase English letters.
• Products are distinct; the input order does not determine suggestion order.

Examples

• Products ["mobile","mouse","moneypot","monitor","mousepad"] and search word "mouse" produce the standard prefix lists beginning with ["mobile","moneypot","monitor"] for m and mo.
• Once a prefix has no matches, that and all longer prefix lists are empty.

Edge Cases

• Fewer than three matches are returned without padding.
• A product equal to the current prefix is a valid suggestion.
• The first character may have no matching product.