Cracking the DoorDash Software Engineer Interview: Navigating a Challenging Coordinate Problem

doordash | Software Engineer | Interview Experience

Interview Date: Not specified
Result: Not specified
Difficulty: Not specified

Interview Process

I was invited for an interview by a recruiter a week ago, and I just completed it this week. The interviewer, a gentleman from China, appeared a bit stern in his LinkedIn photo but was quite friendly in person. The interview involved a coding problem where I was given a set of cities/coordinates and asked to return the nearest city that shares either the x or y coordinate. If there were multiple cities at the same distance, I was to select the one with the smaller name alphabetically.

Initially, I described a brute force approach and then optimized it to sort the x/y coordinates. During the query, I used binary search, which is O(log n). After the interview, I found out that this is a well-known problem, but I hadn’t prepared for it. The problem itself wasn’t difficult, just lengthy with many details. I chose to code in Java, and by the end, I had a small bug. The interviewer mentioned that I had a good understanding of the algorithm and complexity, and that the remaining issues were minor. Overall, I felt it was a lenient interview, as the interviewer indicated that grammar issues could be looked up on Google.

After four years without interviewing, I realized that my skills had declined. While I was comfortable with Java and LeetCode problems, it seems that many companies now focus on verbose questions, which might favor Python.

Technical Questions

  1. Find Nearest Point That Has the Same X or Y Coordinate

Tips & Insights

I noticed that many interviewers I encountered during this job search were around 20 years into their careers. I didn’t feel overly challenged, but the lack of interaction and feedback made me a bit nervous. The questions were not difficult; any failure to write the correct solution was primarily my own fault.