How long should a coding problem take in an interview?

The duration allotted for a coding problem in a technical interview can vary significantly depending on the complexity of the problem, the company, and the specific role for which you are interviewing. However, there are general guidelines and common practices that can give you an idea of what to expect:

Typical Duration

1. Short Problems: For less complex coding problems, often used as a warm-up or to gauge your basic coding skills, you might expect to spend about 10 to 20 minutes. These problems usually require implementing a simple function or algorithm.

2. Medium Complexity Problems: These problems are more common in interviews and typically take between 20 to 40 minutes to solve. They might involve data structures, algorithms, and require a bit more logic and thought about edge cases.

3. Complex Problems: For senior-level positions, or interviews with top tech companies like Google, Amazon, or Facebook, you might encounter more complex problems that require up to 45-60 minutes. These problems often test not only your coding skills but also your problem-solving strategies, understanding of advanced algorithms, or system design principles.

Factors Affecting Duration

• Company Protocol: Different companies have varying protocols for technical interviews. Some might prefer multiple shorter problems to test a range of skills, while others might focus on one or two deeper problems.

• Interview Format: The format of the interview also influences time. In-person interviews might have longer or multiple coding challenges, whereas phone or online coding interviews might be shorter.

• Interviewer’s Discretion: Sometimes, the interviewer may extend the time based on how interesting the discussion around the problem becomes, especially if it involves system design or optimization discussions.

• Candidate's Experience Level: The expected speed can vary based on the level of the position. For example, a senior developer might be expected to solve problems more quickly and efficiently compared to a junior developer.

Best Practices for Candidates

• Time Management: Keep track of time and manage it wisely during the interview. If you're stuck, how you handle the block can be as telling as solving the problem. Communicate your thought process and consider different approaches.

• Clarify Expectations: At the beginning of the problem-solving segment, it can be helpful to ask the interviewer how much time is expected to be spent on the problem. This not only helps in pacing yourself but also sets clear expectations.

• Focus on Quality Over Speed: While it is important to adhere to time limits, focus on writing clean, efficient code with consideration for edge cases. Rushing through a problem and producing buggy or incomplete code can be more detrimental than taking a few extra minutes to refine your solution.

• Practice Under Timed Conditions: To get accustomed to solving problems under time constraints, practice with timed coding challenges on platforms like LeetCode, DesignGurus.io, or HackerRank. This will help you get a better sense of pacing for different types of problems.

Conclusion

While the time for coding problems can vary, preparing to efficiently handle problems within 20 to 40 minutes is a good rule of thumb for most technical interviews. Always ensure you understand the problem completely, ask clarifying questions, and communicate effectively throughout your coding process.