Parse a CSV and Generate a Gift Exchange

Question

This question asks the candidate to demonstrate their ability to parse a CSV file and implement a gift exchange system based on the parsed data.

Codemia · Accepted Answer

To solve the problem of parsing a CSV and generating a gift exchange, I would first read the CSV file line by line. Each line would represent a participant in the gift exchange, containing their name and possibly other relevant information. I would then store this data in a suitable data structure, such as a list or a dictionary, to facilitate the gift assignment process.

1. **Read the CSV file**: Use Python's built-in `csv` module to read the file. 
2. **Store participants**: Create a list to hold participant names. 
3. **Randomly assign gifts**: Shuffle the list and assign each participant a gift from the next participant in the list, ensuring no one gifts themselves. 
4. **Output the results**: Print or return the gift assignments.

Here’s a sample code snippet:
```python
import csv
import random

def generate_gift_exchange(csv_file):
    participants = []
    with open(csv_file, mode='r') as file:
        reader = csv.reader(file)
        for row in reader:
            participants.append(row[0])  # Assuming the first column has names

random.shuffle(participants)
    gift_exchange = {}
    for i in range(len(participants)):
        gift_exchange[participants[i]] = participants[(i + 1) % len(participants)]  # Wrap around

return gift_exchange
```

The time complexity of reading the CSV file and storing participants is O(n), where n is the number of participants. Shuffling the list also takes O(n). Therefore, the overall complexity is O(n). The space complexity is O(n) as well, due to storing the participants in a list.

It is important to handle edge cases such as:
- An empty CSV file: The function should return an appropriate message or handle it gracefully.
- Participants with the same name: Ensure that the gift assignment is still unique.
- A single participant: The function should handle this case by indicating that a gift exchange isn't possible.

To validate the solution, I would write unit tests to check for various scenarios, including:
- Correct gift assignments without self-gifting.
- Handling of empty and malformed CSV files.
- Ensuring that the output is as expected for a given input.

Testing is crucial to ensure the robustness of the implementation.

Parse a CSV and Generate a Gift Exchange

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