Introduction

In this blog post, we will explore how to solve the LeetCode problem "1094" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

There is a car with capacity empty seats. The vehicle only drives east (i.e., it cannot turn around and drive west). You are given the integer capacity and an array trips where trips[i] = [numPassengersi, fromi, toi] indicates that the ith trip has numPassengersi passengers and the locations to pick them up and drop them off are fromi and toi respectively. The locations are given as the number of kilometers due east from the car's initial location. Return true if it is possible to pick up and drop off all passengers for all the given trips, or false otherwise. Example 1: Input: trips = [[2,1,5],[3,3,7]], capacity = 4 Output: false Example 2: Input: trips = [[2,1,5],[3,3,7]], capacity = 5 Output: true Constraints: 1 <= trips.length <= 1000 trips[i].length == 3 1 <= numPassengersi <= 100 0 <= fromi < toi <= 1000 1 <= capacity <= 105

Explanation

Here's the breakdown of the solution:

• Difference Array: Utilize the concept of a difference array to efficiently track the changes in passenger count at each location. Increment the passenger count at the pickup location and decrement it at the drop-off location for each trip.
• Prefix Sum: Calculate the prefix sum of the difference array to determine the current number of passengers at each location.

• Capacity Check: At each location, check if the current number of passengers exceeds the vehicle's capacity. If it does, return false; otherwise, continue.

• Runtime Complexity: O(N + M), where N is the number of trips and M is the maximum location (1000 in this case).

• Storage Complexity: O(M), where M is the maximum location (1000 in this case).

Code

    def carPooling(trips: list[list[int]], capacity: int) -> bool:
    """
    Determines if it is possible to pick up and drop off all passengers for all the given trips.

    Args:
        trips: A list of trips, where each trip is a list [numPassengers, from, to].
        capacity: The capacity of the car.

    Returns:
        True if it is possible to pick up and drop off all passengers for all the given trips, or False otherwise.
    """

    max_location = 0
    for trip in trips:
        max_location = max(max_location, trip[2])

    passenger_changes = [0] * (max_location + 1)

    for num_passengers, start_location, end_location in trips:
        passenger_changes[start_location] += num_passengers
        passenger_changes[end_location] -= num_passengers

    current_passengers = 0
    for change in passenger_changes:
        current_passengers += change
        if current_passengers > capacity:
            return False

    return True