Meta E4 Onsite | Passed

Questions:

680: Valid Palindrome II
- Was asked to think of edge cases like what if input has spaces or punctuation. Sort of evolved into 125. Valid Palindrome.
863: All Nodes Distance K in Binary Tree
- Tree nodes did not have parent pointers. Said that to go exactly K nodes away, we would need graph traversal and need to go up, so told interviewer that we needed to create graph.
- Created a new graph with Node.connections = [list containing parent, left, right nodes], but interviewer seemed unhappy that I created an additional graph object to store left right nodes when I only needed to store parent nodes.

Candidate's Approach

For Valid Palindrome II, I considered edge cases involving spaces and punctuation.
For All Nodes Distance K in Binary Tree, I defended my approach of creating a new graph for clarity in BFS traversal, despite the interviewer's concerns about duplicating the tree.

Interviewer's Feedback

The interviewer seemed unhappy with the decision to create an additional graph object for the left and right nodes, indicating a preference for a more straightforward solution.

Questions:

65: Valid Number
- Was asked to think of edge cases and asked about 0 and its variants (0, 0., .0, 0.0, etc).
347: Top K Frequent Elements
- Gave 3 approaches with time and space complexities: sorting, heap, quick select.
- Interviewer asked to code heap-based approach. Follow up question was to make it O(n) constant time, not O(n) avg time.

Candidate's Approach

For Valid Number, I got stuck coding the edge cases but was able to resolve it with hints.
For Top K Frequent Elements, I proposed bucketing but struggled with the correct implementation as time ran out.

Interviewer's Feedback

The interviewer noted that the approach to make it O(n) constant time was incorrect and indicated that I had chosen the wrong method for bucketing.

Questions:

The question was generic and aligned with common system design questions found in platforms like Leetcode, Strava, Uber, Tinder.

Candidate's Approach

I signed an NDA, so I cannot disclose specifics, but I recommend preparing with mock interviews for system design, which helped me significantly.

Interviewer's Feedback

System Design: Always mention back of the envelope calculations. It shows concern for scaling and can satisfy interviewers looking for that detail.
Coding: Stress the importance of validation testing and edge cases. Be proactive in testing your code against provided examples and consider various input scenarios.