Count Complete Highway Journeys from Toll Logs

Problem Statement

You are given a list of toll records for vehicles on a highway. Each record contains a vehicle_id, a location_id, and a timestamp. A complete journey is defined as a vehicle passing an 'ENTRY' gate followed by an 'EXIT' gate.

Given an unsorted list of records, identify all completed journeys. A journey is valid only if:

1. The vehicle_id matches for both records.
2. The ENTRY timestamp is strictly less than the EXIT timestamp.
3. There are no other records for the same vehicle_id between these two timestamps.

Write a function count_completed_journeys(records) that returns the total count of such valid journeys.

Input Format

records is a list of dictionaries: {'vehicle_id': str, 'type': 'ENTRY' | 'EXIT', 'timestamp': int}

Constraints

• 1 <= records.length <= 10^5
• Timestamps are unique within a vehicle's history.

Example

# Input:
records = [
    {'vehicle_id': 'A', 'type': 'ENTRY', 'timestamp': 10},
    {'vehicle_id': 'A', 'type': 'EXIT', 'timestamp': 20},
    {'vehicle_id': 'B', 'type': 'ENTRY', 'timestamp': 5},
    {'vehicle_id': 'B', 'type': 'ENTRY', 'timestamp': 15},
    {'vehicle_id': 'B', 'type': 'EXIT', 'timestamp': 25}
]
# Output: 2
# Explanation: 'A' has one valid ENTRY-EXIT pair. 'B' has one valid pair (15, 25), 
# as (5, 25) is invalid because there is an entry at 15 in between.