Minimize Car Removals for a Two-Car Bridge

Question

The question asks the candidate to devise a solution to minimize the number of car removals required for a two-car bridge scenario.

Codemia · Accepted Answer

To minimize car removals for a two-car bridge, we need to analyze the arrangement of cars and their positions relative to the bridge. The key is to determine the optimal sequence of cars that can cross the bridge without exceeding the two-car limit. We can utilize a greedy algorithm to make decisions based on the current state of cars.

1. **Identify the positions of the cars**: Create a list of car positions. 
2. **Iterate through the list**: For each car, check if adding it to the bridge exceeds the two-car limit. 
3. **Remove cars if necessary**: If the limit is exceeded, remove the car that has the least impact on future removals. 
4. **Count removals**: Keep track of the number of cars removed during this process.

The time complexity of this algorithm is O(n), where n is the number of cars, since we are iterating through the list once. The space complexity is O(1) if we are modifying the list in place, or O(n) if we need to store additional information.

```python
def minimize_car_removals(cars):
    removals = 0
    bridge = []
    for car in cars:
        if len(bridge) < 2:
            bridge.append(car)
        else:
            # Remove the least impactful car
            removals += 1
            bridge.pop(0)  # Remove the first car
            bridge.append(car)
    return removals
```

Interviewers are looking for a clear understanding of the problem and a logical approach to the solution. They appreciate candidates who can articulate their thought process, justify their algorithm choices, and effectively communicate their code. Additionally, discussing potential edge cases and optimizations demonstrates a deeper understanding of the problem.

Minimize Car Removals for a Two-Car Bridge

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