Arrowstreet’s technical tests are renowned for their emphasis on logic, clarity, and code efficiency. In this blog, we’ll walk through a real programming question from Arrowstreet’s test and illustrate how csoahelp plays a vital role in empowering candidates to excel at every stage.
Question Overview
Question A1
You are given a list of names, where each entry consists of a first and last name. Write a list comprehension to generate all permutations of the names, excluding the last names that are longer than 7 characters.
For example:
names = ["John Smith", "Sally Anderson", "Ashwin Long", "Mandy Kim"]
Expected output:
['John Smith', 'John Long', 'John Kim',
'Sally Smith', 'Sally Long', 'Sally Kim',
'Ashwin Smith', 'Ashwin Long',
'Mandy Smith', 'Mandy Long', 'Mandy Kim']
Requirements:
- Your solution must use a single line of code (list comprehension).
- Assume that there is a predefined variable
namescontaining the input list.
Interview Walkthrough
Clarifying the Problem
At the outset, the candidate asked a series of clarifying questions to ensure a complete understanding of the requirements:
- Candidate: “Are first and last names always separated by a single space?”
- Interviewer: “Yes, you can assume that all names are formatted as ‘First Last’.”
Next, they probed edge cases:
- Candidate: “If all last names are longer than 7 characters, should the function return an empty list?”
- Interviewer: “Yes, in that case, return an empty list.”
At csoahelp, we emphasize the importance of asking clarifying questions during interviews. Our training sessions include a curated checklist of common edge cases to help candidates refine their problem comprehension and avoid mistakes.
Communicating the Solution
After understanding the requirements, the candidate outlined their solution:
- Candidate: “I’ll split each full name into the first and last name using the
split()function. Then, I’ll use a nested list comprehension to pair each first name with valid last names that are 7 characters or fewer.”
The interviewer pressed further:
- Interviewer: “What’s your strategy for ensuring the solution remains efficient for larger datasets?”
- Candidate: “The list comprehension ensures that we process each name entry only once. The nested iteration is necessary to produce all valid permutations, but filtering happens inline, so no unnecessary processing occurs.”
This logical breakdown impressed the interviewer. Such clarity doesn’t happen by chance; csoahelp prepares candidates by simulating similar scenarios and encouraging them to articulate their thought processes effectively.
Handling Follow-Up Questions
During implementation, the interviewer raised an additional concern:
- Interviewer: “How will your code handle cases where some entries are missing either the first or last name?”
- Candidate: “I’ll add a condition to ensure that names are split into exactly two parts before processing. Entries that don’t meet this requirement will be excluded.”
This response demonstrated foresight and robustness in handling edge cases—skills sharpened during csoahelp’s tailored mock interview sessions, where candidates practice responding to nuanced follow-ups.
Complexity Analysis
After completing the solution, the candidate summarized its complexity:
- Candidate: “The time complexity is O(n²), where n is the number of names in the input list. This accounts for pairing every first name with every valid last name. The space complexity is proportional to the number of valid name combinations generated.”
The interviewer appreciated the concise and accurate explanation. csoahelp emphasizes the ability to deliver precise complexity analysis, ensuring candidates stand out in this critical aspect of technical interviews.
Exploring Extensibility
Finally, the interviewer asked:
- Interviewer: “How would you adapt this solution if additional filtering criteria were introduced, such as filtering by the first name’s starting letter?”
The candidate confidently replied:
- Candidate: “I would refactor the filtering logic into a configurable function. This way, new conditions can be applied dynamically without modifying the core comprehension structure.”
This response showcased the candidate’s awareness of code extensibility and modular design. At csoahelp, we train candidates to anticipate such open-ended questions and respond with practical, scalable solutions.
Conclusion
From clarifying requirements to addressing edge cases, analyzing complexity, and exploring extensibility, this Arrowstreet programming test required both technical expertise and strong communication skills. At every stage, csoahelp was pivotal in preparing the candidate to excel.
If you’re preparing for a similar coding test or technical interview, csoahelp offers comprehensive support—from problem-solving techniques to mock interviews that simulate real-world scenarios. Let us help you achieve your career goals with confidence!
经过csoahelp的面试辅助，候选人获取了良好的面试表现。如果您需要面试辅助或面试代面服务，帮助您进入梦想中的大厂，请随时联系我。
If you need more interview support or interview proxy practice, feel free to contact us. We offer comprehensive interview support services to help you successfully land a job at your dream company.
