Overview
This article demystifies the Doordash SDE interview journey, covering common question types (VO coding, system design, behavioral), answering strategies, and high-frequency examples toboost confidence and clarity.
I. Coding Challenges
1. Distribution Path Optimization
Model as pickup & delivery with time windows. Preprocess nodes, build distance matrix, and solve via state-compressed DP or backtracking to minimizetotal route length.
2. Order Status Verification
Validate a sequence of operations (Pi, Di) by tracking pickups in a set and ensuring each delivery corresponds to a prior pickup.
3. Rider Dispatch System
Cluster orders for M riders (≤K orders each) using k-means, then solve small-scale TSP with pickup & delivery constraints per rider to minimize totaldistance.
II. System-Design Questions
- Real-time location tracking for millions of riders (sub-second latency).
- Dynamic pricing engine adjusting delivery fees by demand, supply, weather.
- Real-time order monitoring to detect anomalies (timeouts, duplicate payments).
III. Behavioral (BQ) Questions
- Describe a complex technical problem you solved.
- Handling disagreements with coworkers.
- Approach to learning new technologies.
- Balancing user experience vs. technical constraints.
- Discuss a failed project and lessons learned.
- Coping with high-stress environments.
Conclusion & Tips
Master both technical solutions and thought process. Interview support, VO support, and stay calm under pressure to succeed.
