Meta E4/E5 Phone Screen Reject

Years of Experience: 5

I am unsure why my application was not successful. I have been preparing for the last 3-4 months and have solved approximately 600 coding problems.

The questions were relatively straightforward:

1. Write a method that determines if a string is a palindrome or not (ignore all characters in the string except lowercase and uppercase English characters). I implemented a two-pointer solution and created a set of valid characters for checking. I initially used an if statement instead of an elif statement (in Python), which the interviewer corrected.

2. Given an array of integers (both positive and negative), determine if there is a local minima in the array. (A local minima is defined as an element a[j] such that a[j-1] >= a[j] <= a[j+]. Only compare the right element if the index is 0 and the left element if the index is n-1.) I provided an O(n) solution, but the interviewer prompted me to solve it in log(N) time using binary search. After a few hints, I was able to devise the binary search condition and explain its functionality.

I completed both problems within the allotted time and had 2-3 minutes remaining for general questions.

Two days later, the recruiter informed me that they would not be moving forward with my application.

I am currently employed at a high-frequency trading firm (with approximately 5 years of experience), but I am dissatisfied due to internal politics and a lack of career progression. I am uncertain about the reasons for my rejection. What are Meta's criteria for a successful interview? Shouldn't they assess candidates further through additional rounds to make a comprehensive evaluation of performance?

I am quite confused and frustrated.