Minimum Cars for Rental Requests

Question

This question asks the candidate to determine the minimum number of cars required to fulfill a series of rental requests.

Codemia · Accepted Answer

To solve the problem of determining the minimum number of cars needed for rental requests, we need to consider the time intervals of each rental request. Each request specifies a start and end time, and we need to ensure that cars are available for overlapping requests.

We can approach this problem using a greedy algorithm. The idea is to track the number of cars needed at any given time by processing the start and end times of the rental requests. We will create two lists: one for start times and one for end times, and then iterate through these lists to calculate the maximum number of cars needed at any point.

Here is a Python implementation of the solution:

```python
def min_cars(rental_requests):
    start_times = sorted([request[0] for request in rental_requests])
    end_times = sorted([request[1] for request in rental_requests])
    cars_needed = 0
    max_cars = 0
    i = 0
    j = 0

while i < len(start_times):
        if start_times[i] < end_times[j]:
            cars_needed += 1
            max_cars = max(max_cars, cars_needed)
            i += 1
        else:
            cars_needed -= 1
            j += 1

return max_cars
```
This function first sorts the start and end times, then iterates through them to count the number of cars needed.

The time complexity of this algorithm is O(n log n) due to the sorting of the start and end times, where n is the number of rental requests. The space complexity is O(n) for storing the start and end times.

It is important to consider edge cases such as:
1. All rental requests starting and ending at the same time.
2. No rental requests at all.
3. Requests that do not overlap. 
Testing these cases ensures that the solution is robust and handles various scenarios correctly.

Minimum Cars for Rental Requests

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