Microsoft Principal Applied Scientist Interview Experience — Virtual Onsite, Then the Req Was Cancelled

This was a team under Microsoft MAI working on a web data platform, not the superintelligence team. The role was Principal Applied Scientist.

The phone screen was mostly ML fundamentals and my background. They focused on data-related questions, and there were a few design questions too.

Virtual onsite: What HR listed for each round did not quite match the actual interviews. Basically every round was half coding and half system design, with a small amount of ML fundamentals mixed in, all data-related (imbalance, eval, data drift, etc.). Here are the coding questions from each round.

Round 1 - Coding: Reconstruct Sentence from Dictionary
Given a string with no spaces and a dictionary, add spaces at the right places to restore a meaningful sentence, using only words from the dictionary. If there is no solution, return None. A Word Break variant.

Round 2 - Coding: Maximum Subarray Sum with Concatenation
First find the maximum subarray sum of the array, then find the maximum subarray sum after concatenating the array K times.

Round 3 - Coding: Minimal removal size
Pick the fewest distinct integers and delete all of their occurrences from the array, so that the total number of removed elements is at least half the array length. Return the size of that set. Similar to LeetCode 1338.

Round 4 - ML System Design: Employee Attrition Prediction
Even though this round was also on CodeSignal, I had to choose a model and write some data-processing code, so it was not pure LeetCode style. The task was an HR dataset (attritiondata.tsv, with features like Age / JobRole / MonthlyIncome / OverTime), predict employee attrition and analyze the factors behind it. It leaned toward design: feature processing, model choice, class imbalance, evaluation metrics and interpretability discussion, not just writing code. I used XGBoost, and the interviewer asked some follow-up ML questions about it.

Overall the interviews were not hard, but the annoying part is that two hours after the last round, HR called to tell me the req had been cancelled and the headcount was gone. They told me to wait for further news. In theory my feedback was never even reviewed. I have waited a month and still have heard nothing.