Go Interview with a FAANG engineer

Watch someone solve the longest consecutive sequence problem in an interview with a FAANG engineer and see the feedback their interviewer left them. Explore this problem and others in our library of interview replays.

Longest Consecutive Sequence: Go Interview with a FAANG Engineer - YouTube

Interview Summary

Problem type

Longest Consecutive Sequence

Interview question

1. Given an unsorted array of integers nums, return the length of the longest consecutive elements sequence.
2. Given a binary tree root, return the level order traversal of it as a nested list, where each sublist contains the values of nodes at a particular level in the tree, from left to right.
3. Cutting Trees on a Cliff

You are a landscape designer working on a vertical cliff covered with trees.

The cliff is modeled as a 2D grid:

• 1 = a tree
• 0 = empty rock
• The bottom row is solid ground.
• Two trees are connected if they are adjacent up, down, left, or right (4-directional).

A tree is considered stable if it is connected (through other trees) to at least one tree in the bottom row. If a tree is not connected to any tree in the bottom row, it will fall off the cliff and disappear.

You are given:

• an m x n grid landscape of 0 and 1
• a coordinate cut = (r, c) representing the tree you cut down

Cutting this tree means the cell (r, c) becomes 0 first.

After that, any trees that are no longer stable (no path of 1s to the bottom row) will also fall and become 0.

Return the resulting grid after all unstable trees have fallen.

Interview Feedback

Feedback about Factual Lightning (the interviewee)
Advance this person to the next round?

Yes

How were their technical skills?

3/4
How was their problem solving ability?

4/4
What about their communication ability?

4/4

Feedback for Factual Lightning

Strengths & What Went Well
Factual Lightning demonstrated solid communication skills throughout the interview. He asked thorough clarifying questions, avoided making assumptions, and clearly articulated his reasoning at every step. He showed solid technical understanding, successfully solving all three problems—only one required a small hint.
A major strength was his ability to self-correct. As he explored potential solutions, he recognized when an approach was suboptimal (for example, realizing an O(n²) route wasn’t efficient) and proactively looked for ways to improve it. He was also very receptive to feedback: once he received a hint about identifying the “start” of a sequence, he incorporated it immediately and completed the solution smoothly.
Overall, the interview went very well. He was technically strong, communicated solid, and demonstrated good instincts while navigating different solution paths.

Areas for Improvement

1. Space Complexity Understanding
   One of the solutions had an incorrect space complexity. While his time complexity intuition was strong, improving accuracy around space complexity will help ensure more complete solution analysis.
2. Pattern Recognition & Initial Logic
   In the first question, he initially leaned toward an O(n²) brute-force approach and missed the key insight of locating the “start” of a sequence. A small hint corrected this, but strengthening pattern-recognition will help him identify optimal solutions faster.
3. Premature Coding
   He started coding before solidifying a full verbal solution. While he adjusts well, this can introduce unnecessary errors. It’s better to pause, verbally outline the full end-to-end solution, confirm it with the interviewer, and then begin coding.
4. Syntax & Code Cleanliness
   A few small areas of the code could be cleaner—for example, removing redundant if conditions or simplifying blocks with continue. Not major issues, but tightening syntax will improve overall polish.

Advice for Future Interviews

• Lock in a full verbal solution before coding.
  Confirm with the interviewer that your approach is correct before writing code.
• Brush up on space complexity.
  Ensure your time and space analyses are both correct and complete.
• Improve pattern recognition.
  Especially for problems like sequences, intervals, and sliding windows—always find the structural “trigger” (e.g., start of sequence).
• Continue practicing LeetCode Mediums and some Hard problems.
  Daily mediums + occasional hards will build consistency.
• Research Enduro-style interviews.
  Review Reddit, Blind, and past interview threads. If possible, talk to engineers who interviewed at or worked at Enduro to understand common problem types.

Open Notes

Overall, strong performance and great potential. A few final reminders:

• Reinforce your understanding of space complexity.
• Get comfortable finalizing your full verbal solution before coding.
• After writing code, pause to review if anything can be simplified or made more concise.
• Leverage Reddit, Blind, and personal connections to understand company-specific interview patterns.

Reason for 3/4 in Technical Skills: His initial space-complexity analysis for the first question was incorrect, and the if statement with the continue block could have been written in a cleaner, more structured way.

Communication Note: I was close to giving a 3/4 in Communication because he began coding before fully verbalizing and confirming the complete solution for the first question, which can lead to misalignment in real interview scenarios. However, I consider this a one-off.

Thanks again for the great session, and keep up the strong preparation!

Feedback about Stealthy Elephant (the interviewer)
Would you want to work with this person?

Yes
How excited would you be to work with them?

4/4
How good were the questions?

4/4
How helpful was your interviewer in guiding you to the solution(s)?

4/4

Interviewer was great and explained all the problems clearly. He was good at communicating and it didn't feel like I was completely alone in the room. He helped when needed and was good at affirming whether I was on the right track with something. It was a good experience and he did well to alleviate any stress I had.