Filter Repeated Robot Status Messages

Question

The question asks the candidate to develop a solution that filters out repeated status messages from a robot's message stream, ensuring only unique messages are retained.

Codemia · Accepted Answer

To solve the problem of filtering repeated robot status messages, we need to ensure that only unique messages are retained from a stream of potentially duplicate entries. The goal is to develop an efficient algorithm that can handle this task while considering both time and space complexity.

I will use a set data structure to store unique messages since sets inherently do not allow duplicate entries. This will allow us to efficiently check for existing messages and add new ones. The algorithm will iterate through the list of messages, adding each message to the set if it is not already present.

Here is a Python implementation of the solution:

```python
def filter_repeated_messages(messages):
    unique_messages = set()
    filtered_messages = []
    for message in messages:
        if message not in unique_messages:
            unique_messages.add(message)
            filtered_messages.append(message)
    return filtered_messages
```
This function iterates through the input list of messages, checks if each message is already in the set, and if not, adds it to both the set and the result list.

The time complexity of this solution is O(n), where n is the number of messages, because we are iterating through the list once. The space complexity is O(m), where m is the number of unique messages stored in the set. This is efficient given that we only store unique entries.

Interviewers will look for a clear explanation of the chosen data structure and its benefits, as well as the candidate's ability to articulate their thought process. They will also assess the efficiency of the solution and how well the candidate anticipates potential edge cases, such as empty inputs or large datasets.

Filter Repeated Robot Status Messages

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