xAI interview notes, page 6 of 9

“I knew LRU cold but LFU tripped me up for a minute because the tie-breaking rule means you need to track both frequency AND insertion/access order within each frequency bucket.” The rest of the author's notes on Software Engineer interview at xAI, Technical Phone Screen round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.

“The basic SET/GET/DELETE part took me about two minutes.” The rest of the author's notes on Software Engineer interview at xAI, Technical Phone Screen round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.

“Pretty straightforward.” The rest of the author's notes on Software Engineer interview at xAI, Technical Phone Screen round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.

“The rapid follow-ups are what get you.” The rest of the author's notes on Software Engineer interview at xAI, Technical Phone Screen round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.

“My first instinct was to just check every vocab token at every position, which is obviously O(n * vocab_size) and they basically said as much before I finished explaining it.” The rest of the author's notes on Machine Learning Engineer interview at xAI, Technical Phone Screen round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.

“Classic LRU with a twist: instead of counting slots, you're tracking total weight and evicting until you're back under budget.” The rest of the author's notes on Software Engineer interview at xAI, Technical Phone Screen round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.

“I had an answer but it felt a bit rehearsed coming out.” The rest of the author's notes on Software Engineer interview at xAI, Onsite - Behavioral / Leadership round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.

“This was not what I expected.” The rest of the author's notes on Software Engineer interview at xAI, Technical Phone Screen round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.

“I picked a project that was genuinely messy and I think that was the right move, but I fumbled the structure a bit.” The rest of the author's notes on Software Engineer interview at xAI, Onsite - Behavioral / Leadership round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.

“I went straight to parallel merge sort, split the array into chunks and assign each chunk to a thread, merge at the end.” The rest of the author's notes on Software Engineer interview at xAI, Technical Phone Screen round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.