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
Anthropic logo
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
Anthropic logo
Anthropic
Medium
Software Engineer Locked

Implement a Batch Image Processor

This question evaluates a candidate's competency in image processing operations and parallel/concurrent programming, covering basic transformations (g...

Coding & Algorithms
11
0
82 people solved
Apr 1, 2026
Anthropic logo
Anthropic
Medium
Software Engineer Locked

Implement a longest-match tokenizer

This question evaluates string-processing and algorithmic implementation skills for greedy longest-match tokenization, including handling runs of unma...

Coding & Algorithms
4
1
73 people solved
Oct 19, 2025
Anthropic logo
Anthropic
Hard
Software Engineer

Find duplicate files and apply image operations

Part A — Find duplicate files by content You are given a list of directory records. Each record is a string describing a directory path followed by on...

Coding & Algorithms
115
0
772 people solved
Oct 15, 2025
Anthropic logo
Anthropic
Medium
Machine Learning Engineer Locked

Implement an LRU cache

This question evaluates competency in designing efficient key-value caching mechanisms, enforcing capacity constraints and eviction policies while mai...

Coding & Algorithms
22
0
349 people solved
Feb 27, 2026
Anthropic logo
Anthropic
Medium
Software Engineer

Detect duplicate files by content

Detect duplicate files by content in a filesystem. Given access to a directory tree, return groups of file paths that have identical byte content. Min...

Coding & Algorithms
12
0
188 people solved
Aug 1, 2025
Anthropic logo
Anthropic
Hard
Software Engineer Locked

Build a least-recently-used cache

This question evaluates a candidate's competence in designing and implementing efficient in-memory cache mechanisms, focusing on data structures, evic...

Coding & Algorithms
4
0
35 people solved
Feb 8, 2026
Anthropic logo
Anthropic
Hard
Software Engineer

Crawl Same-Domain Links

Implement a Python function that crawls a website starting from a seed URL and returns all unique pages reachable within the same domain. Assume a hel...

Coding & Algorithms
16
0
114 people solved
Jan 6, 2026
Anthropic logo
Anthropic
Medium
Software Engineer

Design file deduplication across nested directories

Design and implement a file deduplication tool that, given a root directory, identifies groups of duplicate files. Requirements: traverse nested direc...

Coding & Algorithms
21
0
204 people solved
Aug 14, 2025
Anthropic logo
Anthropic
Hard
Software Engineer

Implement staircase printing and distributed mode/median

Problem A: Print a “staircase” pattern Implement a function that prints a staircase with n rows. Input - An integer n (n >= 1) Output - Print n lines....

Coding & Algorithms
67
0
923 people solved
Nov 19, 2025
Anthropic logo
Anthropic
Medium
Software Engineer

Design file deduplication algorithm

Design an algorithm to deduplicate files in a storage system. Compare fixed-size versus content-defined chunking and explain how you would choose hash...

Coding & Algorithms
12
0
201 people solved
Sep 6, 2025
Anthropic logo
Anthropic
Medium
Software Engineer

Apply bitwise tricks for performance

For an integer-heavy inner loop, propose bit-level optimizations that reduce branches and memory traffic: e.g., population count usage, fast modulo by...

Coding & Algorithms
22
0
162 people solved
Sep 6, 2025
Anthropic logo
Anthropic
Medium
Software Engineer

Implement file deduplication at scale

Write a program to deduplicate files in a very large directory tree. Identify groups of identical files without loading entire files into memory. Outl...

Coding & Algorithms
99
0
759 people solved
Sep 6, 2025
Anthropic logo
Anthropic
Medium
Software Engineer

Design and implement a Python solution

Design and implement a solution in Python for a problem specified by the interviewer. Outline your approach and chosen data structures, justify key de...

Coding & Algorithms
26
0
243 people solved
Sep 6, 2025
Anthropic logo
Anthropic
Medium
Software Engineer

Implement Python LRU cache with args and persistence

Implement an LRU cache in Python as a decorator or class that correctly supports variable-length positional arguments and keyword arguments. Ensure th...

Coding & Algorithms
46
0
314 people solved
Aug 1, 2025
Anthropic logo
Anthropic
Medium
Software Engineer

Implement a same-host web crawler

Implement a web crawler. Given a start URL and a function get_links(url) -> list of URLs, return all URLs that share the same hostname as the start. A...

Coding & Algorithms
14
0
102 people solved
Aug 1, 2025
Anthropic logo
Anthropic
Medium
Software Engineer

Implement thread-safe blocking queue

Question Design and implement a thread-safe bounded blocking queue that supports concurrent enqueue and dequeue operations using standard synchronizat...

Coding & Algorithms
8
0
13 people solved
Jul 29, 2025
Anthropic logo
Anthropic
Medium
Software Engineer Locked

Same-Domain Web Crawl (BFS)

This question evaluates a candidate's ability to implement graph traversal using breadth-first search while applying a domain-matching filter and dedu...

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

Implement a Least-Recently-Used Cache

Design and implement an in-memory least-recently-used cache. Requirements: - The cache is initialized with a positive integer capacity. - Implement ge...

Coding & Algorithms
1
0
7 people solved
Apr 19, 2026
Anthropic logo
Anthropic
Hard
Software Engineer

Compute Exclusive Time from Stack Events

Compute Exclusive Time from Stack Events Given entry and exit events from one thread, compute the total exclusive running time of each function. The i...

Coding & Algorithms
0
0
11 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.

Explore more Anthropic Coding & Algorithms interview questions

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

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