Given a train schedule with departure city, arrival city, start time, end time, and duration, and given a source and destination, find the sequence of trains that gets you there at the earliest possible time.

"I got into the loop through a backdoor-ish hiring manager route instead of a cold apply, and for L4+ I had to have a soft match with a team before the loop even started. My process was a recruiter alignment call, the GHA questionnaire, one phone screen, two onsite technicals, and a standard Googliness behavioral. What stood out was how collaborative and non-LeetCodey it felt, especially the phone screen, which was basically a live algorithms conversation that pushed on first principles instead of rehearsed patterns. I also learned that Google is doing more team matching before hiring committee now, because a hiring manager's statement of support can strengthen your packet if one round is only lean hire. I ended up accepting because the interview experience was consistently positive and honestly much better than how Google interviews are usually portrayed online."