# Reason About Recursive Key Search in Nested JSON Given an in-memory JSON-like object whose values may include strings, numbers, booleans, lists, or nested objects, explain how to search the entire structure for a queried key and return its associated value. Identify the result semantics that must be clarified before writing an exact implementation. ### Constraints & Assumptions - The input is already a structured object, not serialized JSON text. - Lists may contain values or nested objects. - The source shows successful lookups but does not define duplicate-key or missing-key behavior. ### Clarifying Questions to Ask - If the key occurs at several depths or branches, should the function return one value or every match? - Are objects and lists traversed in a defined order? - What should a missing query return, and how should arbitrary JSON values cross the API boundary? ```hint Separate discovery from representation First decide which matching paths count; only then choose how the corresponding structured values are returned. ``` ### What a Strong Answer Covers - Recursive or iterative traversal of objects and lists. - A stated duplicate-key and missing-key contract rather than an invented first-match rule. - Returning structured values without lossy or language-dependent text serialization. - Complexity, recursion depth, cycles outside valid JSON, and representative tests. ### Follow-up Questions 1. How would you return the full path to every matching key? 2. How would you handle a structure deep enough to overflow the call stack?