Walmartlabs

The position is Stuff, software engineer. The scheduling was a bit chaotic; there were two interviews scheduled for the same time, but HR helped resolve it, moving Round 1 to Round 3. Also, the information provided by HR was incorrect; they said on the phone that Round 1, Round 2, LeetCode, and Round 3, SD. In reality, Round 1 was moved to the next interview with the same interviewer, half SD and half LeetCode. Round 2: 692 variation, Item ID + timestamp Event. Record the Event; the user provides the timestamp window and k, and queries the top k most accessed items within this interval. Follow-up questions include how to handle the need to clean the map and how to handle situations where the event timestamps are not guaranteed to be ordered. I used TreeMap, so I've already solved the second follow-up question. Regarding the first follow-up question, since I confirmed with him that the timestamp provided by the client could be arbitrary, all timestamps had to be retained. Later, he changed the requirements, asking how to handle situations with specific timestamps. I mentioned three methods: Scheduled task, during insert, or during search. Round 3: SD (Shortcut Design), asking how to build a stock trend website that requires real-time processing, mainly focusing on storage and synchronization methods. Round 1: SD Flash Sale, but he changed the question to "Build a button 'Notify me' for the flash sale." He asked which design pattern to use for SD. I didn't immediately recognize it, but after confirming with him, I realized it was Singleton, Factory, or Abstract Factory, which he confirmed. Perhaps I've been using HLD (Hardware-Local Design), while he wanted LLD (Low-Local Design). The last 20 minutes were spent on LeetCode 2204 (hard). They gave me an extra 10 minutes. I had the ideas, but unfortunately, I was too nervous and didn't think to use DFS to find the circle, instead getting stuck on UnionFind. The result probably wasn't great. They talked to me for another 10 minutes at the end, and I felt they were emphasizing the importance of stuff job design and implementation. It's rare to see such a nice Indian, but the questions were a bit too difficult. I feel like I'm in trouble.