What should I say in a coding interview?

In a coding interview, what you say is just as important as how you code. Interviewers are not only evaluating your technical abilities but also your communication skills, problem-solving approach, and how well you handle challenges. Here’s a guide on what you should say during each stage of a coding interview:

1. Clarify the Problem First

Before jumping into the coding, ensure that you fully understand the problem. Asking clarifying questions shows the interviewer that you’re thoughtful and careful in your approach.

What to Say:

• "Can you clarify if [input] will always be [specific type/condition]?"
  • Example: "Will the input array always be sorted?"
• "Should I consider edge cases like an empty input or negative numbers?"
  • Example: "Should I account for an empty string as input?"
• "What’s the expected time or space complexity for an optimal solution?"
  • Example: "Is there a particular time complexity I should aim for, like O(n)?"
• "Let me summarize the problem to make sure I understand it correctly."
  • This helps ensure you're on the same page before you start coding.

2. Talk Through Your Thought Process

As you think through the problem, verbalize your thought process. This helps the interviewer understand your reasoning and approach to solving the problem.

What to Say:

• "I’m thinking of using a brute-force approach first, and then I’ll try to optimize it."
  • This shows that you can break the problem down and aim for efficiency later.
• "I’ll use a hash map here because it allows for constant-time lookups."
  • Explain why you’re choosing a particular data structure or algorithm.
• "I see two possible approaches here: I can either use a recursive solution or iterate over the input. Let me think about which one might be better."
  • This shows you’re evaluating different solutions rather than diving in headfirst.
• "This approach has a time complexity of O(n²), but I’ll aim for O(n) by optimizing [specific part of the solution]."
  • Always mention the time and space complexity as you explain your approach.

3. Write the Code While Explaining It

While writing your code, continue explaining your logic. Don’t assume the interviewer can read your mind or follow every line without context. Commenting on your code as you write it also helps if you’re unsure about a step or need to think aloud.

What to Say:

• "I’ll start by initializing this variable to keep track of [specific thing]."
  • Example: "I’ll initialize max_sum to store the maximum sum of subarrays."
• "This loop will go through the array once, and I’ll update the hash map as I go."
  • Show how your logic will handle the problem incrementally.
• "I’m using a sliding window technique here to avoid recomputing overlapping subproblems."
  • Explain why you’re using a specific algorithm or optimization.
• "Now I’m adding a check for edge cases, such as when the input is empty."
  • Showing attention to edge cases is critical, and verbalizing it assures the interviewer that you’re thorough.

4. Discuss Edge Cases

As you code, mention how you plan to handle edge cases. It’s important to show that you’re thinking about all possible inputs, not just the typical or simple ones.

What to Say:

• "I’m thinking about how this will handle edge cases, like an array with all negative numbers or an empty string."
• "For edge cases like when there’s only one element, my solution will still return the correct result because I’m checking this condition."
• "If the input is null or empty, I’ll handle that by returning 0 at the start of the function."

5. Test Your Solution with Example Inputs

After writing your code, walk through it step by step with sample inputs, explaining how the solution works in each case. This shows that you’re careful and that your solution is robust.

What to Say:

• "Let’s test the solution with this example input: [input]."
  • Example: "For the array [1, -2, 3, 4], the maximum subarray sum should be 7, and here’s how my code achieves that."
• "This line should handle the case where the input array is empty, returning 0."
  • Talk about specific cases and how the code handles them.
• "For an input of [3, 5, 1], the hash map will store each element, and I’ll iterate through the array like this..."
  • Walk through a small example manually and describe how each part of the code executes.

6. Analyze the Time and Space Complexity

After coding and testing, always discuss the time and space complexity of your solution. Interviewers want to see that you’re thinking about efficiency.

What to Say:

• "The time complexity of this approach is O(n) because I’m only looping through the array once."
  • This shows that your solution is optimal or close to optimal.
• "The space complexity is O(1) since I’m only using a few extra variables, not any additional data structures."
  • Even if the solution is optimal in time, the interviewer may want to hear about space complexity.

7. Be Honest If You’re Unsure

If you’re unsure about a solution or make a mistake, don’t panic. Interviewers appreciate candidates who are open about their limitations and try to fix mistakes rather than trying to cover them up.

What to Say:

• "I’m not entirely sure if this is the most efficient approach, but I’ll explain what I’m thinking and try to improve it as I go."
• "I realize that this part of the solution might have an edge case I didn’t account for. Let me fix that by [explaining your fix]."
• "I made an error here. Let me go back and correct it by doing [fix]."

8. Ask for Feedback and Show Willingness to Improve

At the end of the interview or while you’re solving the problem, engage with the interviewer by asking if they have suggestions or feedback on your approach.

What to Say:

• "Is there anything you would recommend to optimize this further?"
  • Shows you’re open to feedback and willing to learn.
• "Does this solution meet the expected performance criteria?"
  • Invites the interviewer to provide feedback or additional hints.
• "I’m open to suggestions if you think there’s a better way to approach this."
  • Demonstrates humility and openness to improving your solution.

9. Ask Questions When Stuck

If you get stuck or can’t think of a solution, don’t stay silent. It’s better to ask questions or request hints than to sit quietly, as the interviewer wants to see your problem-solving skills, not just a perfect answer.

What to Say:

• "I’m a bit stuck on how to optimize this part. Can you give me a hint on whether I’m on the right track?"
  • Asking for help is okay and can guide you toward the solution.
• "I’m considering using a recursive solution here, but I’m not sure if it’s the best approach. What do you think?"
  • This shows that you’re trying to think critically but are open to suggestions.

10. Summarize Your Solution

After you’ve finished coding and testing your solution, provide a brief summary of what you did and why. This helps the interviewer see the complete picture.

What to Say:

• "To summarize, I used a sliding window approach with a hash map to ensure that I can find the longest substring without repeating characters in linear time."
• "I started with a brute-force approach and then optimized it to reduce the time complexity to O(n)."
• "This solution handles edge cases like empty inputs and repeated characters because of the checks I implemented."

Conclusion

In a coding interview, it’s important to think aloud and communicate your thought process clearly. Clarifying the problem, explaining your approach, testing your solution, and discussing time and space complexity are key parts of the process. Even if you make mistakes or get stuck, be honest and show that you’re trying to learn and improve. Good communication, combined with problem-solving skills, will leave a positive impression on your interviewer.