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Interview Questions
Practice 9403 coding, system design and machine learning questions from 546 companies, sorted by role, topic and interview round. Every question has step-by-step hints, a code runner that supports 8 languages and an AI mentor; members also get the full solution walkthrough.
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Showing 961–990 of 3640 results
- CoupangMediumSoftware EngineerDescribe your proudest project and dive deep
This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Describe your proudest project and dive deep states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Behavioral & LeadershipOnsite - CoupangMediumSoftware EngineerDesign a PKI for internal mTLS and certificates
This question evaluates a candidate's competency in PKI architecture, cryptographic key management, certificate lifecycle (issuance, renewal, revocation), and operational security for internal mTLS and related signing use cases.
System DesignOnsite - CoupangMediumSoftware EngineerDesign an IAM system for services and users
This question evaluates understanding of Identity and Access Management concepts including authentication and authorization flows, role- and policy-based permissions, temporary credential handling, multi-tenant access control, auditing, and scalability considerations.
System DesignOnsite - CoupangMediumSoftware EngineerDesign large video upload for a YouTube-like app
This question evaluates a candidate's ability to design scalable, reliable large-file upload subsystems, testing competencies in distributed storage, resumable transfers, data integrity, processing pipelines, security, and observability.
System DesignOnsite - CoupangMediumSoftware EngineerFind shortest distance between two islands
This question evaluates understanding of grid-graph traversal and shortest-path concepts, including identification of connected components and reasoning about minimal bridging distance between regions.
Coding & AlgorithmsOnsite - CoupangMediumSoftware EngineerWalk Through Your Proudest Project, What Made It Special, and What You Would Change
Behavioral project deep-dive for software engineers: describe the project you are proudest of, what made it distinctive, what you learned, and what you would do differently. It tests concise storytelling, clear personal ownership, technical depth, measurable results, and honest self-reflection on past decisions.
Behavioral & LeadershipOnsite - CreditkarmaMediumMachine Learning EngineerDesign a Revenue Ranking Platform
This problem tests your ability to design a multi-stage ranking system that balances business revenue goals with user relevance, specifically addressing sparse conversion data and long-term user retention.
ML System DesignOnsiteRankingRecommendationMulti-task Learning - CrestaMediumSoftware EngineerBuild a Tool-Calling Chat Agent That Searches and Books Flights via a REST API
An AI-assisted coding round: turn a Python starter script into a terminal chat agent that uses LLM tool calling to search flights, save passenger details and book a flight through a three-endpoint REST API. It tests tool schemas, a multi-step tool loop, ID handling, booking safeguards and error handling.
Software Engineering FundamentalsOnsite - CrestaMediumSoftware EngineerDesign a Robust Feature Flag Evaluation Engine
Implement an in-memory feature flag evaluation engine that evaluates flags against user attributes using rule predicates, deterministic percentage rollouts, and a true-wins resolution policy.
Software Engineering FundamentalsOnsiteSoftware ArchitectureData StructuresHashing - CrestaMediumSoftware EngineerDesign an Evaluation Platform for AI Agents Across Prompt and Model Changes
An ML system design question about a platform that lets teams evaluate AI agents and measure how a change of system prompt or model affects quality, tool use and response speed. It tests evaluation design, scoring with references and LLM judges, statistical comparison of versions and scalable execution.
ML System DesignOnsite - CrowdstrikeMediumSoftware EngineerCount connected components in a binary grid
This problem tests your ability to model a 2D grid as a graph and use graph traversal algorithms like DFS or BFS to count distinct connected components.
Coding & AlgorithmsOnsiteGraphsDFSBFS - CrowdstrikeMediumSoftware EngineerDesign a file upload and scanning report system
This problem tests your ability to design a distributed, asynchronous system that handles high-throughput file uploads, coordinates multi-engine security scanning, and provides reporting capabilities.
System DesignOnsiteScalabilityAsynchronousSecurity - CrowdstrikeMediumSoftware EngineerImplement an In-Memory Key-Value Cache with Expiry, Then Sketch a Redis-Like Server
Implement an in-memory key-value cache in the spirit of Redis, with get, set, delete and per-key expiry, then briefly discuss how a Redis-like server is built and where caches fit in a system. It tests data structure choices, expiry and eviction logic, thread safety, and practical knowledge of caching patterns.
Software Engineering FundamentalsOnsite - CrowdstrikeMediumSoftware EngineerMaximize the minimum value along a grid path
This problem tests your ability to combine binary search on the answer with graph traversal techniques (BFS/DFS/Union-Find) to solve optimization problems on a 2D grid.
Coding & AlgorithmsOnsiteBinary SearchBFSDFS - CrowdstrikeMediumSoftware EngineerReview a Sample Python Function Aloud and Label Every Finding by Severity
Review a short hypothetical Python function that builds a user profile from a database query and a billing-service call, narrating your reasoning aloud. The exercise tests how you read unfamiliar code and whether every comment is clearly labeled as must-fix, could-improve or a personal preference.
Software Engineering FundamentalsOnsite - CrusoeEasySoftware EngineerDesign a Slack-Like Messaging Platform
Design a real-time team messaging platform supporting channels, direct messages, message persistence, and presence tracking. The design tests your ability to model conversations, ensure reliable and ordered message delivery, and handle high-throughput fan-out.
System DesignOnsiteDistributed SystemsWebSocketsPub/Sub - CrusoeEasySoftware EngineerImplement Interval Overrides and Top-K Strings
Implement interval override logic for half-open ranges and calculate the top-k labels based on total active duration with lexicographical tie-breaking.
Coding & AlgorithmsOnsiteintervalssortinghash-table - DRWMediumData ScientistCompute Markov steady state and expectations
Compute Markov steady state and expectations evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathOnsite - DRWEasyData ScientistDerive eigenvalues and sum for inverse matrix
Derive eigenvalues and sum for inverse matrix evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathOnsite - DRWHardQuantitative ResearcherExpected Dart Score for a Bivariate Normal Throw with Ring Scoring
Calculate the expected score of a dart throw modeled by a zero-mean bivariate normal distribution with circular scoring rings, calibrated using a known hit probability inside the inner ring.
Statistics & MathOnsiteProbabilityBivariate NormalExpected Value - DRWHardQuantitative ResearcherExpected Rounds Until a Shopping-Cart Line Empties Under Random Transfers
Tests modeling discrete-time Markov chains, formulating hitting-time difference equations, and solving symmetric random walk absorption problems analytically.
Statistics & MathOnsiteMarkov ChainsProbabilityRandom Walk - DRWHardQuantitative ResearcherExpected Tosses Until HHT Given HHT Appears Before HTH
Calculate the probability that the coin sequence HHT appears before HTH in repeated fair tosses, and find the conditional expected number of tosses until termination given that HHT appears first.
Statistics & MathOnsiteprobabilitymarkov-chainsconditional-expectation - DRWHardQuantitative ResearcherExpected Winnings in a Random-Walk Money Collection Game on 45 Stones
Calculates a player's expected winnings in a random-walk money collection game on an odd-sized circle of stones using Gambler's Ruin and parity arguments.
Statistics & MathOnsiteprobabilityrandom-walkgamblers-ruin - DRWHardQuantitative ResearcherPosterior Probability of a Two-Headed Coin After Three Heads
This question tests the application of Bayes' theorem, conditional likelihoods, and posterior probability updates given sequential binary observation data.
Statistics & MathOnsiteProbabilityBayes' TheoremQuantitative Research - DRWHardQuantitative ResearcherProbability the Two Strongest Teams Meet in a 16-Team Knockout Final
Calculate the probability that the two highest-ranked teams face each other in the championship match of a 16-team single-elimination tournament with probabilistic match outcomes.
Statistics & MathOnsiteprobabilitycombinatoricsconditioning - DRWMediumData ScientistSolve Markov and distribution expectation problems
This interview question evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer for Solve Markov and distribution expectation problems states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathOnsite - DRWMediumData ScientistSolve movie ratings, array, release scheduler
This question tests algorithmic problem-solving across three domains: greedy array optimization, tree-based data structure design, and efficient sequence merging. It evaluates practical coding ability and complexity analysis, commonly used in quantitative and data science interviews to assess how candidates identify inefficiencies and select the right data structure to improve performance.
Coding & AlgorithmsOnsite - DRWMediumData ScientistSolve three algorithmic tasks in Python
This question evaluates proficiency in dynamic programming, range-query data structures (Fenwick/segment tree), sorting and two-pointer techniques, and algorithmic complexity analysis within the Coding & Algorithms domain for Python-based implementation.
Coding & AlgorithmsOnsite - DatabricksMediumSoftware EngineerAdd Sliding-Window Get and Put Activity Metrics to a Key-Value Store
Design and implement an in-memory key-value store that tracks read and write throughput (operations per second) over configurable sliding windows.
Software Engineering FundamentalsOnsitedata-structuressliding-windowsystem-design - DatabricksHardSoftware EngineerBuild a Constant-Time Snapshot Set Iterator
Design a mutable ordered integer set that supports constant-time snapshot iterator creation without copying the live dataset, preserving insertion order and handling elements that are removed and re-added.
Coding & AlgorithmsOnsiteData StructuresDesignLinked List
Coupang
Cresta
Crowdstrike
DRW
Databricks