Find Neighboring Records by Identifier

Problem Statement

You are given a list of unique numerical identifiers representing job posting IDs, sorted in ascending order. You need to design a service that, given a specific target ID, returns the ID immediately preceding it (the predecessor) and the ID immediately following it (the successor).

If the target ID is not present in the list, the service should return None for both values. If the target is the first or last element, return None for the missing neighbor.

Implement the class NeighborFinder with the following structure:

class NeighborFinder:
    def __init__(self, ids: list[int]):
        # Initialize with a sorted list of unique integers
        pass

    def get_neighbors(self, target_id: int) -> tuple[int | None, int | None]:
        # Returns (predecessor, successor) for the target_id
        pass

Constraints

• 1 <= len(ids) <= 1,000,000
• -10^9 <= ids[i] <= 10^9
• The input list is strictly sorted.

Examples

Example 1: Input: ids = [10, 20, 30, 40], target_id = 20 Output: (10, 30)

Example 2: Input: ids = [10, 20, 30, 40], target_id = 5 Output: (None, None)

Example 3: Input: ids = [10, 20, 30, 40], target_id = 40 Output: (30, None)