DoorDash Coding & Algorithms Interview Questions

DoorDash Coding & Algorithms interview questions typically emphasize practical problem solving under time pressure, clear code, and product-minded tradeoffs. What’s distinctive is a bias toward realistic engineering tasks—scheduling, graph traversal, and array/string manipulation appear often—combined with an expectation that you communicate tradeoffs, test edge cases, and iterate quickly. Interviewers assess algorithmic thinking, correctness, complexity reasoning, and the ability to refactor or extend solutions when given follow-ups. Expect an initial technical screen followed by a loop of 2–4 interviews that blend live coding with behavioral and sometimes system-design conversations. For interview preparation, prioritize consistent timed practice on medium-to-hard problems, rehearse speaking your thought process, and run mock interviews in your target language and editor. Refresh core data structures, common patterns (DFS/BFS, two pointers, heaps, hash maps, dynamic programming), and time/space analysis. Finish prep by practicing end-to-end: state assumptions, outline an approach, code defensively, and validate with tests so you can both solve and clearly explain your solutions during the loop.

62 Questions 1 Company08.04.2026
Showing 20 results
Role
DoorDash logo
DoorDash
Medium
Software Engineer

Can two names match with ≤2 swaps?

You are given two restaurant names represented as strings s and t of equal length (same character set, case-sensitive). In one operation, you may swap...

Coding & Algorithms
5
0
94 people solved
Jan 13, 2026
DoorDash logo
DoorDash
Medium
Software Engineer

Calculate Courier Earnings

Design a function to calculate total courier pay from a set of delivery orders. Assume time is represented as integer minutes, and intervals are half-...

Coding & Algorithms
9
0
71 people solved
Jan 9, 2026
DoorDash logo
DoorDash
Medium
Software Engineer

Compute courier pay and implement load balancing

Problem 1: Compute courier (delivery driver) pay You are given a sequence of delivery-related events for a courier during a day. Your task is to compu...

Coding & Algorithms
121
0
949 people solved
Dec 16, 2025
DoorDash logo
DoorDash
Hard
Software Engineer

Find longest common ordered restaurant list

You have two delivery drivers who each have a pickup plan represented as a list of restaurant IDs (strings). Because there is only one car, the combin...

Coding & Algorithms
26
0
197 people solved
Nov 7, 2025
DoorDash logo
DoorDash
Medium
Data Scientist

Implement minimum window substring with counts

Implement min_window_with_counts(s, t) Task Write a function: - min_window_with_counts(s: str, t: str) -> tuple[int, int] that returns the inclusive (...

Coding & Algorithms
8
0
103 people solved
Oct 13, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

Design dasher-to-order assignment algorithm

You are building a real-time 'dasher picker' that assigns delivery drivers (Dashers) to incoming orders. Define objective(s) (e.g., minimize ETA and c...

Coding & Algorithms
1
0
13 people solved
Sep 6, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

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...

Coding & Algorithms
12
0
84 people solved
Sep 6, 2025
DoorDash logo
DoorDash
Medium
Software EngineerSenior+

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...

Coding & Algorithms
21
0
296 people solved
Sep 6, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

Find minimum processing rate

Find minimum processing rate You are given an array piles where piles[i] is the number of items in the i-th pile and an integer H (total hours). Find ...

Coding & Algorithms
5
0
48 people solved
Aug 9, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

Generate the next lexicographic array arrangement

Generate the next lexicographic array arrangement Given an integer array nums (which may include negative numbers and duplicates), modify nums in plac...

Coding & Algorithms
4
0
54 people solved
Aug 8, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

Compute nearest courier for each customer

Compute nearest courier for each customer You are given two sets of 2D points: customers C = {c1..cn} and active couriers (dashers) D = {d1..dm}. Each...

Coding & Algorithms
5
0
84 people solved
Aug 8, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

Compute earliest arrival in time-grid

Question LeetCode 778. Swim in Rising Water – Given an n x n integer grid where grid[i][j] is the earliest time you can enter the cell, starting from ...

Coding & Algorithms
2
0
52 people solved
Aug 4, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

Solve string match and DashMart BFS

Question Implement a string-matching function that returns the first index of a pattern in a text (akin to LeetCode 28 Implement strStr()). 2) “Dash M...

Coding & Algorithms
7
0
66 people solved
Aug 4, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

Implement string matching with follow-up

Question Given a text T and a pattern P, implement a function firstIndex(T, P) that returns the starting index of the first occurrence of P in T, or -...

Coding & Algorithms
7
0
52 people solved
Jul 31, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

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...

Coding & Algorithms
13
0
45 people solved
Jul 29, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

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...

Coding & Algorithms
9
0
27 people solved
Jul 29, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

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...

Coding & Algorithms
6
0
30 people solved
Jul 29, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

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...

Coding & Algorithms
10
0
5 people solved
Jul 29, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

Design a hierarchical path registry

Design a hierarchical path registry Implement an in-memory hierarchical path registry. Support: create(path, value) to create a new path with an integ...

Coding & Algorithms
4
0
52 people solved
Jul 28, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

Find max distance between alive tree nodes

Find max distance between alive tree nodes Given a binary tree, define alive nodes. Base case: alive nodes are the leaves. Find the maximum distance (...

Coding & Algorithms
7
0
57 people solved
Jul 28, 2025

Frequently Asked Questions

How difficult are DoorDash Coding & Algorithms interview questions?
DoorDash Coding & Algorithms questions are typically in the medium-to-hard range for software-engineer roles, though difficulty varies by level. New-grad and entry roles usually see solid LeetCode-medium problems that test arrays, hashes, trees, and two-pointer or sliding-window patterns. Mid and senior interviews often include harder algorithmic puzzles, performance trade-off discussions, or problems with follow-ons that push toward optimal time/space. Interviewers evaluate correctness, algorithmic efficiency, coding clarity, and communication. Expect to demonstrate both problem-solving speed under time pressure and the ability to iterate from brute force to optimized solutions.
What is the typical DoorDash interview process and where do Coding & Algorithms questions appear?
DoorDash’s technical funnel usually begins with a recruiter screen followed by one or more technical coding screens and then an onsite or virtual loop. Coding & Algorithms questions commonly appear in the initial phone or online technical screen and in two on-site coding rounds; some teams also include pair-programming or debugging-style exercises. For mid-senior levels, coding rounds are paired with system-design and behavioral interviews. Coding problems test core algorithmic skills and often connect to logistics or metrics-oriented scenarios to see how you map real product needs to data-structure solutions.
How much time should I spend preparing for DoorDash Coding & Algorithms interviews?
Preparation time depends on your baseline: candidates with recent algorithm practice often need three to five weeks of focused review, while those returning to algorithms may require eight to twelve weeks. A useful plan balances daily problem practice with weekly timed mock interviews. Early sessions should refresh fundamental data structures and complexity analysis, moving to medium/hard problems and time-constrained mock rounds as the interview approaches. In the final two weeks, emphasize problem articulation, code cleanliness, and explaining trade-offs aloud. Adjust pacing if you’re targeting a specific team or seniority level.
Which subtopics should I prioritize when studying for DoorDash Coding & Algorithms questions?
Prioritize core data structures and algorithmic patterns that recur across coding rounds: arrays, hash tables, strings, sliding window, two pointers, sorting, and search techniques. Trees and graph traversals, BFS/DFS, dynamic programming fundamentals, and common greedy strategies are also important. Practice windowed/streaming aggregations and median/heaps patterns for real-time metrics problems. Strong complexity intuition, edge-case handling (including NULLs or empty inputs), and trade-off reasoning for time and space are essential. Equally important is coding craft: clear function signatures, named variables, simple tests, and incremental refinement to an optimal solution.
What are standout tips and common pitfalls to avoid in DoorDash Coding & Algorithms interviews?
Standout tips include talking through your thought process, proposing a brute-force approach before optimizing, writing clear, well-structured code, and testing edge cases aloud. Use simple examples to validate ideas and explain complexity trade-offs. Avoid common pitfalls like jumping into coding without a plan, ignoring integer overflow or null/empty cases, and failing to communicate assumptions. Don’t forget to ask clarifying questions about input size, mutability, and expected behavior. For senior candidates, connect algorithmic choices to production considerations such as scalability and maintainability rather than focusing only on asymptotic savings.

Explore more DoorDash Coding & Algorithms interview questions

Real questions from candidate reports, grouped by role, topic and company.

By role
Other categories at DoorDash
Coding & Algorithms questions at other companies
Browse all