Three people conducted my interview. I felt that the interviewers didn't ask particularly relevant questions.

The first interviewer asked me questions about my past experience but struggled to understand my explanations. Perhaps he wasn't interested and was astonished when I mentioned that, as part of a feature, we executed Groovy scripts from Java classes, with the scripts stored in the database. His question then was, "Did you store serialized objects in the DB?" He had difficulty understanding that classes were compiled at runtime. Incidentally, I wrote a recursive function to identify valid palindromes within a string and successfully applied it to the test string.

The second interviewer likely worked primarily with binary data. His first question was about counting set bits in a 32-bit integer. I admitted that I don't deal with binary data daily and last used bitwise operators in school ten years ago. However, I offered an array-based solution where I counted the number of set bits, but it wasn't sufficient. Another question involved a binary stream of data, which I again converted to a string example and explained my approach. While explaining, I started with the general case, ignoring edge cases, to which the interviewer said, "Why are you not writing the entire function?" Then, when I began writing the complete function, he stated, "You spend way too much time writing corner cases." Really?

He then asked a question about traversing all nodes of a graph, to which I provided a recursive solution with neighbors. He didn't understand the following Java for loop: for(Node n : nodeList) and said I was writing pseudocode. I explained that it was valid syntax, but he didn't believe me. I believe he came from a world where everything was binary and he didn't deal with Java daily, while I come from a world that uses Java and non-binary data daily.

Honestly, try to connect with the candidate's background and ask questions relevant to your job. Testing someone's algorithmic acumen is one thing, but at least make sure you're asking the right questions.

Give me all the permutations of valid palindromes in a string.

I strongly believe this is a highly flawed question, at least from the example expected output. I hope someone can prove me wrong.

It is a combination of three different problems:

1. Get all possible subsets of a string.
2. Check those subsets for the possibility of a palindrome.
3. Get permutations of valid palindromes.

I highly doubt that this can be solved in a span of 45 minutes.

Find the count of set bits in a 32-bit buffer.

Easy if you know bitwise operations, but the last time I encountered bitwise operations was 10 years back in school.

Given a buffer of binary data, separate data into different buffers based on a separator. Also, within valid data, discard specific bits and concatenate bits.

Given a bidirectional graph, traverse all the nodes starting at any node. This one was easy.