Doordash Software Engineer Interview Questions
Master your tech interview with our curated database of real questions from top companies.
Determine equality after limited swaps
Question LeetCode 1790. Check if One String Swap Can Make Strings Equal Follow-up: Given two strings, determine if they can become anagrams of each ot...
Discuss project motivation and challenges
Project Deep-Dive (Software Engineer — Phone Screen) Prepare a structured deep-dive on one significant project you led or owned. In 8–10 minutes, cove...
Count changed nodes in N-ary trees
Question Given two N-ary trees (old and new versions) where each node has a key (string), value (int), and list of children, compute how many nodes ar...
Find names similar by one swap
Question LeetCode 859. Buddy Strings – Given a target string and a list of strings, return all list entries that can match the target by swapping at m...
Implement string-path file system operations
Question LeetCode 1166. Design File System – extended to support Create(path, value), Get(path), Set(path, value) and Delete(path) with validation rul...
Design notification and project architecture
System Design: Multi-Channel Notification Platform Design a scalable Notification System that supports real-time and scheduled messages across multipl...
Compute cart total with best promotion
Assume you are implementing a checkout price calculator for an online shopping cart. You are given: - A list of items in the cart. Each item has: - ...
Generate the next lexicographic ordering
Given an array of integers, rearrange the elements in-place to form the next sequence in lexicographic order relative to the current arrangement; if n...
Design review system with voting and rewards
Design: Scalable Product Reviews with Voting and Rewards Context You are designing a reviews feature for a large e-commerce marketplace. Customers can...
Explain conflict resolution and growth
Behavioral & Leadership: Conflict, Mistake, and Project Deep Dive To assess collaboration, ownership, and technical leadership, answer the following t...
Compute dasher pay from deliveries
Given a list of delivery events for dashers (e.g., dasherId, pickupTime, dropoffTime, distance, tip, and optional bonuses) and a set of pay rules (e.g...
Design a notification system
System Design: Multi-Channel Notification Platform Context Design a multi-tenant notification platform that delivers messages across email, SMS, and m...
Deep dive a project's architecture
System Design Deep Dive: Past Project Provide a deep dive on one production project you owned or co-built. Assume the audience has not seen your syste...
Design a scalable notification system
Design a Multi‑Channel Notification System (Push, SMS, Email) with SLAs, Preferences, and Spike Resilience Context You are designing a notifications p...
Design consistent hashing for sharding
Design a Consistent-Hashing Router with Replication You are building a stateless router that maps arbitrary keys (for example, request IDs or cache ke...
Find nearest courier for each customer
Given two sets of 2D points: customers C = {c1..cn} and active couriers D = {d1..dm}, return for every customer the nearest courier by geographic dist...
Implement string pattern matching
Implement a function that finds the first occurrence of a pattern P in a text T and returns the starting index (or -1 if not found). Follow-ups: compa...
Implement round-robin load balancer
Implement a load balancer that distributes incoming requests across N backend servers in strict round-robin order. Requirements: ( 1) Support addServe...
Compute delivery times on a grid
You are given a 2D grid with cells marked as 'M' (warehouses), 'C' (customers), 'X' (obstacles), and '.' (roads). You can move up, down, left, or righ...
Describe best project and technical details
Behavioral Prompt: Project You’re Most Proud Of (Software Engineering Onsite) This prompt assesses ownership, impact, technical depth, decision-making...