Microsoft

"Imagine you are designing the undo/redo engine for a multi-user collaborative code editor": I was handed this prompt to resolve conflicting character insertions across asynchronous network calls, so I walked through an Operational Transformation (OT) state-vector model before showing how a conflict-free replicated data type (CRDT) like Logoot eliminates central lock contention. "We have a memory-constrained embedded IoT device reading erratic analog voltage signals": The panel challenged me to filter out bursty electrical noise and isolate periodic sensor pulses in real time without buffering the entire waveform, which I tackled by implementing a rolling 1D Fast Fourier Transform (FFT) paired with a circular running-variance window. "Assume an airline needs to route crew members through unpredictable storm delays with minimum overnight hotel costs": The question forced me to balance maximum flight leg coverage against strict regulatory rest periods, which I mapped as a Minimum-Cost Maximum-Flow (MCMF) problem on a time-expanded DAG, computing the optimal reassignments using the successive shortest path algorithm.