Anthropic Coding & Algorithms Interview Questions

Anthropic Coding & Algorithms interview questions tend to skew practical and systems-minded rather than purely contrived puzzles. Expect live, timed coding rounds (often in a shared Python environment or CodeSignal), system-design-style problems for scaling and reliability, and behavioral questions tied to safety and collaboration. Interviewers evaluate problem decomposition, correctness, edge-case handling, performance trade-offs, code clarity and modularity, and how you reason about concurrency, data mutation, and robustness under changing requirements. Deep follow-ups are common: a working solution is a starting point, not the finish line. For interview preparation focus on building polished, testable implementations of multi-stage problems (for example in-memory stores, streaming/aggregation tasks, or concurrent data structures), practicing clear verbal articulation of trade-offs, and rehearsing concise safety- and values-aligned stories. Time-boxed mock interviews in the same tools you’ll use, steady practice with Python standard library idioms, and walking through post-solution optimizations will pay off. Emphasize readability, small iterative steps, and how you validate and harden code — those habits map directly to what Anthropic seeks.

79 Questions 1 Company07.08.2026
Showing 20 results
Role
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Anthropic
Medium
Software Engineer

Design an in-memory banking service

Design an in-memory banking service supporting timestamped operations and edge-case semantics. Implement: ( 1) create_account(id, t): Create a new acc...

Coding & Algorithms
105
1
928 people solved
Sep 6, 2025
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Anthropic
Medium
Software Engineer

Design a single- and multi-threaded web crawler

Web Crawler (single-threaded, then multi-threaded) You are given: - A starting URL startUrl (e.g., "http://news.example.com/a/index.html"). - An inter...

Coding & Algorithms
64
0
527 people solved
Oct 26, 2025
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Anthropic
Medium
Machine Learning Engineer Locked

Convert Samples into Event Intervals

This question evaluates understanding of array and sequence processing, run-length encoding concepts, and interval representation for time-ordered tra...

Coding & Algorithms
15
0
94 people solved
Apr 7, 2026
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Anthropic
Medium
Software Engineer

Implement a Banking System

Design and implement an in-memory banking system. All operations are processed in non-decreasing timestamp order. Account identifiers are strings. Mon...

Coding & Algorithms
9
0
67 people solved
May 24, 2026
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Anthropic
Medium
Software Engineer

Find Duplicate Files

Implement a file deduplication tool. You are given a root directory containing many files. Return groups of duplicate files. Two files are duplicates ...

Coding & Algorithms
12
0
80 people solved
Mar 2, 2026
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Anthropic
Medium
Software Engineer Locked

Fix a Corrupted Bootloader Instruction

This question evaluates the ability to simulate instruction-level program execution, reason about control flow and mutable program state (instruction ...

Coding & Algorithms
9
0
51 people solved
May 19, 2026
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Anthropic
Hard
Machine Learning EngineerSenior+ Locked

Implement a Simplified DNS Resolver

This question evaluates understanding of DNS semantics (name normalization, A and CNAME records, alias chains and cycle detection), robust error handl...

Coding & Algorithms
23
0
203 people solved
May 16, 2026
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Anthropic
Medium
Software Engineer AI Locked

Maximum-Length Unique-Character Subset

This question evaluates a candidate's ability to combine bitmasking with backtracking or subset enumeration to maximize a constraint over combinations...

Coding & Algorithms
0
0
7 people solved
Jun 23, 2026
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Anthropic
Medium
Software Engineer Locked

Path Resolution with Symbolic Links

This question evaluates a candidate's ability to implement filesystem-style path resolution, including handling relative and absolute paths, dot compo...

Coding & Algorithms
0
0
8 people solved
Jun 23, 2026
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Anthropic
Medium
Software Engineer Locked

In-Memory Key-Value Database with Nested Transactions

This question evaluates a candidate's ability to design a data structure that layers transactional state over a committed base, testing skills in nest...

Coding & Algorithms
5
0
22 people solved
Jun 23, 2026
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Anthropic
Medium
Software Engineer

Convert stack samples to trace events

Question Implement convertToTrace(samples) that, given a chronologically ordered vector of stack samples (each sample contains a timestamp and a call-...

Coding & Algorithms
181
2
676 people solved
Jul 29, 2025
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Anthropic
Medium
Software Engineer

Generate outputs for images and pipelines

You are given m input images and n processing pipelines. - Each pipeline is an ordered list of k operations (e.g., resize, rotate, crop, blur, color t...

Coding & Algorithms
115
0
1247 people solved
Nov 10, 2025
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Anthropic
Medium
Software Engineer Locked

Implement an in-memory DB with TTL backup/restore

This question evaluates implementation and reasoning skills for an in-memory nested key→field→value store with TTL-based expirations, snapshot backup/...

Coding & Algorithms
79
2
873 people solved
Feb 11, 2026
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Anthropic
Medium
Software Engineer

Parse and Reconstruct Stack Trace

Given a multi-line stack trace string from a single thread (e.g., each frame is in the form 'at Module::Function(file:line)'), design and implement a ...

Coding & Algorithms
44
0
666 people solved
Sep 6, 2025
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Anthropic
Medium
Machine Learning Engineer

Convert stack samples to execution trace

You are given sampling-profiler output: a list of Sample objects ordered by timestamp ascending. Each Sample has (t: float, stack: list[str]) where st...

Coding & Algorithms
53
0
856 people solved
Sep 6, 2025
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Anthropic
Medium
Software Engineer

Detect duplicate files efficiently

You are given access to a very large file system containing file paths and read access to file contents. Design an algorithm to identify groups of fil...

Coding & Algorithms
46
0
816 people solved
Sep 6, 2025
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Anthropic
Medium
Software Engineer Locked

Design an IPv4 Address Iterator

This question evaluates a candidate's ability to represent and iterate IPv4 addresses, covering parsing, numeric arithmetic with carry between octets,...

Coding & Algorithms
15
0
114 people solved
Jan 10, 2026
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Anthropic
Medium
Software Engineer Locked

Build a concurrent web crawler

This question evaluates understanding of concurrent programming, synchronization, thread safety, and graph traversal as applied to a multithreaded web...

Coding & Algorithms
22
0
144 people solved
Apr 5, 2026
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Anthropic
Medium
Machine Learning Engineer Locked

Implement a web crawler using a provided API

This question evaluates understanding of web crawling mechanics, URL/hostname filtering, graph traversal concepts, and concurrent fetching, assessing ...

Coding & Algorithms
35
0
325 people solved
Feb 11, 2026
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Anthropic
Hard
Software Engineer

Group Duplicate Files by Content

Group Duplicate Files by Content Given a snapshot of files, return groups of paths whose complete contents are identical. The interview report preserv...

Coding & Algorithms
0
0
6 people solved
Apr 16, 2026

Frequently Asked Questions

How hard are Anthropic Coding & Algorithms interview questions?
Anthropic’s coding and algorithms rounds are generally described as challenging but practical: they test core algorithmic thinking under time pressure rather than obscure trick questions. Expect problems that evaluate data structures, complexity reasoning, and the ability to produce clean, testable code in a shared environment (often Python). Rounds are timed and may feel brisk, so interviewers look for correct, readable solutions and sound tradeoffs rather than clever one‑liners. Candidates frequently report industrial-style tasks that escalate in complexity, which rewards steady problem decomposition and careful edge‑case handling.
What is the typical interview process and where do Coding & Algorithms questions appear?
For software roles at Anthropic, coding and algorithmic questions commonly appear in the initial online assessment and in one or more live technical rounds during the onsite loop. The process often starts with a recruiter screen, a timed coding challenge (e.g., CodeSignal), then one or two live coding interviews plus system design and behavioral rounds during the onsite. Coding segments focus on algorithmic problem solving, debugging and small project-style tasks, while later technical rounds may connect those problems to design or team-specific work. Expect interviews to be organized by the org you apply to (Research vs Applied).
How should I schedule my preparation for Anthropic Coding & Algorithms interviews?
A focused 4–8 week timeline is effective: begin with two weeks of core data structures and algorithm review (arrays, strings, trees, graphs, hashing, sorting, and complexity), followed by two weeks of timed practice on platforms that mimic assessments (practice CodeSignal-style tasks and full-length challenges). Reserve the final 1–2 weeks for mock live interviews, system design refreshers, and polishing language-specific idioms and quick I/O in Python. Sprinkle daily short debugging and read‑your‑own‑code sessions to improve clarity and speed. Adjust intensity based on role seniority and your baseline skills.
Which subtopics within Coding & Algorithms should I prioritize?
Prioritize fundamentals that interviewers use to judge practical engineering ability: arrays and strings, hashing, trees and graph traversals, dynamic programming basics, sorting and selection, and complexity analysis. Equally important are problem decomposition, writing testable code, handling edge cases and nulls, and explaining time/space tradeoffs. For Anthropic specifically, practice implementing small in‑memory systems or multi-step tasks that grow in complexity, and be comfortable with Python standard library tools and fast I/O. Performance considerations and readable, maintainable code are weighed alongside algorithmic correctness.
What are the most helpful tips and common pitfalls to avoid?
Communicate your thought process clearly, start with a correct brute force approach, and iterate toward optimizations while checking edge cases; interviewers reward clarity over premature cleverness. Write modular, testable code and run small examples to validate assumptions. Manage time: if stuck, state tradeoffs and pivot to a simpler, working solution. Common pitfalls include ignoring input constraints, failing to handle nulls or boundaries, and producing unreadable one-off solutions. Also be ready to discuss design decisions and tradeoffs rather than only delivering a final answer.

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