Bloomberg New Grad Software Engineer Interview Experience — Rejected After a Van Eck Sequence Question

Painful memory from an interview I did last year, around September-October. I was in a funk for a month after it.

Bloomberg's bar is basically two medium-to-hard questions, and you're expected to get the optimal solution.

It was a virtual interview, and the interviewer showed up 10 minutes late. I sat in the meeting watching her keep logging in and out, and when she finally turned her camera on, she said let's start with an easy one. Then she slowly typed out the problem letter by letter in the shared editor, and I was getting anxious just watching her do it.

I had never seen this problem on LeetCode or on the forums. I had AI restate it for me afterward and it looks like it's the Van Eck sequence:

Given an integer n, define a sequence a as follows:

• a[0] = 0
• For i >= 1:
  • If a[i-1] has appeared before (i.e., the same value exists somewhere in the range [0, i-2]):
    • a[i] = (i - 1) - last_index
    • where last_index is the last position at which a[i-1] previously appeared
  • Otherwise:
    • a[i] = 0

Return the value of a[n-1].

a[0] = 0
a[1] = 0 (0 has not appeared before)
a[2] = 1 (0 last appeared at index 0 → 1 - 0 = 1)
a[3] = 0 (1 has not appeared before)

Then as I was writing it, I completely lost my way on this problem. My brain just wasn't fully awake that morning — my code trying to track the index was squirming around like a worm, and I could not get it straight. By the time I finished there were maybe 15 minutes left, and the interviewer said, well, let's leave it there, do you have any questions. Two days later, the rejection letter came.

Lesson learned: for every other company's interview after that, I made sure to schedule it in the afternoon.