Did the Pfizer OA and technical screen last month for a mid-level SWE opening on their supply chain platform team. Here's the full breakdown for anyone prepping.
Online Assessment
HackerRank platform. Two problems, 72-hour window to submit. No proctoring in my case.
Problem 1: Given a list of drug shipment records with timestamps and quantities, find the earliest time window where total quantity exceeds a threshold. Basically a sliding window with some parsing. Medium difficulty, definitely doable if you've touched Leetcode.
Problem 2: A shortest path problem on a graph of distribution centers. Classic BFS. The pharma framing made it sound harder than it was.
Scoring felt binary: pass/fail, not partial credit. I got a callback within 3 business days.
Technical phone screen
One engineer, Google Doc or a similar no-IDE environment. I got a problem involving a nested JSON structure. The actual coding part was maybe 30 minutes, and the rest was walkthrough and discussion. They weren't looking for perfectly optimal solutions; they wanted to see me think out loud and explain tradeoffs.
One thing that caught me off guard: they asked about testing strategy. Not just 'how would you test this function' but 'what test cases would catch regressions in production.' I wasn't ready for that depth. Have an answer.
Onsite coding round
This one had slightly harder difficulty. I'd call it medium-to-hard. String manipulation + dynamic programming adjacent. They gave a hint about 20 minutes in when I hadn't cracked the DP transition. Appreciated that, honestly.
Key takeaway: they seem to weight code clarity and explanation over raw speed. I've done FAANG rounds where you feel punished for every extra second. This wasn't that. More collaborative.
If you're prepping, Leetcode mediums are sufficient. Do a handful of graph and sliding window problems and you'll be in good shape. Don't over-index on hard problems.