Make the collaboration observable
For pair programming practice, agree who is implementing and who is checking the requirement and reasoning. Explain decisions as you work and invite correction. This original exercise focuses on role handovers and a changing requirement rather than another solo coding problem.
Applicants to English-speaking European teams can use it with a friend or colleague. The driver and navigator labels are practice conventions here, not a claim that every employer uses the same interview structure. Confirm the shared editor and permitted assistance in advance.
Change a cancellation rule together
A fictional function decides whether an appointment can be cancelled. The first requirement allows cancellation before the appointment starts. After you implement that behaviour, the practice interviewer changes the rule: cancellation must happen at least two hours before the start. All timestamps in the exercise are explicit UTC instants.
The driver describes a small change. The navigator asks what happens exactly at the two-hour boundary and checks tests before adding more conditions. Then swap roles. The second driver explains the existing work before editing it so the handover does not become silent replacement.
| Case | Question for the pair |
|---|---|
| More than two hours before | Does the revised rule allow cancellation? |
| Exactly two hours before | Does 'at least' include this boundary? |
| Less than two hours before | What result should the function return? |
| Malformed timestamp | Should validation reject it or does another layer handle it? |
Narrate the change without filling every silence
A useful explanation is: 'I will compare the appointment instant with the current instant using the agreed cutoff. Before changing the code, can we confirm that exactly two hours qualifies? I will add that boundary test so the wording is explicit.' The navigator can then challenge the assumption before implementation.
If you spot an error in your partner's change, describe the failing input rather than grabbing the keyboard. For example: 'This test uses a local date string although we agreed UTC instants. Could the environment affect its interpretation?' Give the partner space to inspect the issue.
Follow-up questions to test your reasoning
- What do you say before taking over as driver?
- How do you handle disagreement on the boundary?
- What changes if the requirement is expressed as a local business date?
After the exercise, check whether both participants could explain the final rule. A working implementation with an unexplained handover leaves collaboration untested. Note when a clarification prevented rework and when narration became distracting.
Repeat with a different change request
Change the next requirement to a rescheduling rule and repeat the role swap. Keep the code small enough that the practice concerns reasoning and communication. Use tools only under the agreed practice conditions, and follow the employer's rules in the real interview.
This is an original Cluegent practice exercise. Its scenario, example wording and suggested timings are illustrative, not an employer's assessment or scoring system. Use genuine experience in a real interview.
For optional preparation, paste the exercise into Cluegent as a typed prompt and ask for one follow-up at a time. Review the reasoning before adopting suggested wording. Redact personal and employer-confidential information. Try Cluegent on Windows or macOS; check the current trial and paid terms before downloading. Follow the employer's rules during an actual assessment.
Browse the Europe interview preparation collection or try Debugging interview practice: investigate a duplicate order.
Sources checked
These official references support the guide. Product details and technical documentation can change; check the linked source for current information.
Where Cluegent helps
Cluegent supports permitted live workflows with transcript context, typed prompts, screenshot-aware answers, resume context, custom response behavior, quick action buttons, and a private desktop overlay. It is most useful when you already understand the subject and need help staying structured under pressure.
Frequently asked questions
How can I practise a pair programming interview?
Work on a small task with a partner, state assumptions, add boundary tests and switch implementation roles with a clear handover.
Should I talk continuously while coding?
Explain meaningful decisions and invite questions. Leave space for concentration and for your partner's reasoning.