## Problem You have `k` passengers, each with a list of acceptable pickup stops (given as stop IDs). A carpool vehicle can service at most one route. Find all stop IDs that appear in every passenger's acceptable list — i.e., stops where all passengers can be picked up. Return the result sorted ascending. If no common stop exists, return an empty list. ```python def shared_stops(passenger_stops: list[list[int]]) -> list[int]: pass ``` **Example:** ``` Input: passenger_stops = [ [1, 2, 5, 7], [2, 5, 9], [3, 5, 2] ] Output: [2, 5] ``` ## Follow-ups 1. What if each passenger has a priority ranking of stops — find the stop with the best average rank across all passengers? 2. How does your solution change if passenger lists are sorted? 3. If passengers stream in one at a time, how would you maintain the common stop set incrementally? 4. Extend to find stops shared by at least `m` out of `k` passengers.

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Shared Pickup Route: Find Minimum Common Stops for Carpooling Passengers

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Problem You have k passengers, each with a list of acceptable pickup stops (given as stop IDs). A carpool vehicle can service at most one route. Find all stop IDs that appear in every passenger's acceptable list — i.e., stops where all passengers can…

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