# Find Unreachable Objects in a Heap Graph Heap objects now contain references to other addresses. Each object is represented as `[address, references]`, where `references` is a list of integer addresses. An object is reachable if its address appears in `stack_addresses` or if it can be reached transitively by following references from a reachable object. Return every unreachable address in the same relative order as `heap_objects`. ### Function Signature ```python def dead_object_addresses( stack_addresses: list[int], heap_objects: list[list], ) -> list[int]: ... ``` ### Example ```text Input: stack_addresses = [10] heap_objects = [ [10, [20]], [20, [30]], [30, [20]], [40, [10]] ] Output: [40] ``` ### Constraints - `0 <= len(heap_objects) <= 200_000` - Heap-object addresses are unique. - Every object record has exactly two fields: an integer address and a list of integer references. - The total number of references is at most `400_000`. - References and stack roots that do not identify a heap object are ignored. - Cycles and self-references are allowed. ### Clarifications - Reachability follows outgoing references only. - Return primitive integer addresses in heap input order and do not mutate the inputs. ### Hints - Treat addresses as vertices and references as directed relationships. - Ensure each reachable object is processed at most once, even when cycles exist.