DoorDash Senior Engineer Interview: Code Craft and System Design

For doordash, the code craft interview is a bit tricky and different. But luckily it has a small question bank and I think only 2 questions so I was able to practice both of those questions on a websi

For doordash, the code craft interview is a bit tricky and different. But luckily it has a small question bank and I think only 2 questions so I was able to practice both of those questions on a website. That helped a lot. #### Coding Problem: Finding the nearest dasher to a location I took a BFS approach from the start and the interviewer gave me the thumbs up to implement it.

Follow-up:

Return all equidistant closest locations Discussed: Handling unreachable destinations Multi-source BFS optimization for repeated queries Where I did well: Quickly identified BFS as the right approach and implemented cleanly Handled the follow-up extension smoothly

Result All the test cases

passed, interviewer seemed happy. --- #### Code Craft Problem: Make a payment system for dashers.

Edge cases I tried to handle: - Overlapping delivery windows - Multiple orders at different stages - Time window boundaries - Concurrent order limits

Result Interviewer seemed satisfied with the incremental approach and handling of edge cases. I had practiced all the code craft problems here before so it was a lot easier for me. --- #### System Design Problem: Review System with Voting It's covered by this recently asked doordash design questions listed here: https://offerretriever.com/questions/31 Lukily I looked through and tried to practice all the design questions ahead of time, but sadly I didn't spend too long thinking about this one. It went mostly ok, I choked a bit while talking about adding a cache, but we moved on from it and the rest went alright Could have discussed more about sharding strategies for high-volume restaurants

Result Feedback was mixed, felt I could have gone deeper on scalability ⚠️ --- #### Behavioral Standard behavioral round covering: - Past project experiences - Conflict resolution scenarios - Red flag screening questions (why leaving current role, team dynamics, etc.) - Deep dive into a challenging project Pretty straightforward, no surprises here. Interviewer was friendly and conversational.

Result Went smoothly ✅ --- Overall Takeaways For system design, I should have prepared in-depth for all the recently asked system design questions. My questions was on that list but so sad I didn't prepare it well even though knowing it ahead of time