Count Complete Highway Journeys from Sensor Logs

A highway has multiple sensor locations: entry, exit, and intermediate checkpoints. Each sensor logs when a car passes. You are given time-ordered logs logs. Each log entry indicates that at a given time, a sensor saw a specific car. Define a journey as: the same car completes an entry -> exit within the logs (with zero or more checkpoints in between). Each completed entry-to-exit counts as one journey. Implement a function that counts how many journeys are present in logs. Input (make assumptions explicit in your implementation) logs: list of records sorted by time each record includes at least: timestamp, sensorId, carId a sensor metadata source that maps sensorId to entry / exit / checkpoint Output integer: total number of completed journeys Typical constraints logs are already sorted by timestamp carId/sensorId are strings or integers a car may appear in multiple journeys Example tests (for self-check) Single completed trip: entry(A) -> checkpoint -> exit(A) => 1 Incomplete: entry(A) -> checkpoint => 0 Interleaving cars: entry(A), entry(B), exit(A), exit(B) => 2 Multiple trips same car: entry(A), exit(A), entry(A), exit(A) => 2 Checkpoints outside a trip: checkpoint(A), entry(A), checkpoint(A), exit(A) => 1 Example Input logs=[(1,'E','A'),(2,'C1','A'),(3,'X','A')], sensorType={'E':'entry','X':'exit','C1':'checkpoint'} Output 1