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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.
- 9403
- Questions
- 546
- Companies
- 11
- Topics
- 8
- Languages
Showing 1831–1860 of 3640 results
- LyftMediumSoftware EngineerImplement command-driven in-memory key-value database
This question evaluates a candidate's ability to design efficient in-memory data structures and implement transactional semantics for operations like SET/GET/DELETE/COUNT, including handling nested transactions, rollbacks, and commits.
Coding & AlgorithmsOnsite - LyftMediumSoftware EngineerImplement paginated retrieval of transactions
Implement paginated retrieval of transactions evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsOnsite - LyftMediumSoftware EngineerIn-Memory Key-Value Store with Nested Begin, Commit, and Rollback Transactions
A coding question to implement an in-memory key-value store with begin, set, unset, commit and rollback, where transaction blocks can be nested and committed changes can no longer be rolled back. It tests how state is recorded per block, restoring keys that were absent, nested commit semantics, and operation complexity.
Software Engineering FundamentalsOnsite - LyftMediumData ScientistInvestigate Causes of Driver WOW Score Drop
Investigate Causes of Driver WOW Score Drop evaluates metric design, causal reasoning, experiment setup, diagnostics, SQL/statistical checks, and recommendations in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Analytics & ExperimentationOnsite - LyftMediumSoftware EngineerMinimum Window Substring with Repeated Required Characters
Tests the sliding window technique and frequency counting to find the shortest substring containing all required characters with their exact multiplicities in linear time.
Coding & AlgorithmsOnsiteSliding WindowTwo PointersHash Table - LyftMediumData ScientistOptimize Driver Repositioning for Minimal Pickup Time
This question evaluates spatial algorithms and real-time optimization for ride dispatch together with interval scheduling and capacity planning competencies, covering skills in computational geometry, routing, demand forecasting, and temporal overlap reasoning.
Coding & AlgorithmsOnsite - LyftMediumData ScientistQuery and transform marketplace data in SQL/Python
This question evaluates mastery of data manipulation and analytics skills in the Data Manipulation (SQL/Python) domain, including SQL aggregation and window functions, time-based joins and grouping, deduplication of status streams, handling late-arriving events, and implementing rolling metrics using both SQL and pandas.
Data Manipulation (SQL/Python)Onsite - LyftEasySoftware EngineerReconstruct a BST from Preorder Traversal
Reconstruct the exact binary search tree represented by a preorder traversal of unique integers. Handle empty and completely skewed inputs at scale while preserving the intended tree rather than balancing it.
Coding & AlgorithmsOnsite - LyftMediumSoftware EngineerRotting Oranges
Compute how many simultaneous spread steps are needed to rot every reachable orange using multi-source grid traversal.
Coding & AlgorithmsOnsite - LyftMediumSoftware EngineerSolve grid compromise spread with BFS
This question evaluates proficiency in graph traversal and grid-based simulation, specifically multi-source breadth-first search, state propagation modeling, and algorithmic complexity analysis within the Coding & Algorithms domain, emphasizing practical application of implementation and reasoning.
Coding & AlgorithmsOnsite - LyftMediumSoftware EngineerSolve substring and worker assignment
This pair of problems evaluates competencies in string processing and multiplicity handling as well as scheduling and resource-allocation for interval tasks, testing the ability to choose and apply appropriate data structures while managing time and space complexity.
Coding & AlgorithmsOnsite - LyftMediumSoftware EngineerWrapper Over a Paginated Page API That Fetches the Next N Words
A coding question that wraps an external paginated API, where each page returns a variable number of words, behind a fetch(n) method that returns the next n words in order. It tests handling words left over between calls, requests that span several or empty pages, lazy fetching, the end of the content, and API failures.
Software Engineering FundamentalsOnsite - Marshall WaceMediumSoftware EngineerCompute max events in any 60-second window
This question evaluates understanding of timestamp and array processing, sliding-window or two-pointer techniques, and the ability to analyze time and space complexity when counting events within fixed-size intervals.
Coding & AlgorithmsOnsite - Marshall WaceMediumSoftware EngineerFind users with multi-country successful logins
This question evaluates proficiency in relational data manipulation, text normalization, aggregation, deduplication, and sorting within the Data Manipulation (SQL/Python) domain, focusing on practical query-writing and data-processing skills.
Data Manipulation (SQL/Python)Onsite - MathWorksMediumSoftware EngineerAnswer SDET internship behavioral interview questions
This set of behavioral prompts evaluates communication, structured storytelling, technical judgment, learning agility, conflict resolution, and alignment of career goals—core competencies for an SDET internship.
Behavioral & LeadershipOnsite - MathWorksMediumSoftware EngineerCompare Core Networking and Language Runtime Concepts
Compare pointer ownership and storage duration, HTTP with HTTPS, and TCP with UDP using concrete technical examples. Strong responses separate guarantees from common implementations, connect concepts to production failures, and avoid simplistic claims about memory or network speed.
Software Engineering FundamentalsOnsite - MathWorksMediumSoftware EngineerDesign a Scalable Product Authentication Platform
Design authentication infrastructure for browser and API clients using email and password today with room for external identity providers later. Cover secure credentials, session lifecycle, abuse resistance, recovery, database choices, trust boundaries, and a path to tenfold traffic.
System DesignOnsite - MathWorksMediumSoftware EngineerMinimize reduction cost and validate equal-sum pairs
This problem tests your ability to use greedy strategies with priority queues to minimize reduction costs and use hash-based frequency mapping to identify valid pairs that satisfy specific sum conditions.
Coding & AlgorithmsOnsiteGreedyMin-HeapHash Map - MavenclinicMediumSoftware EngineerSolve two interview coding problems
This problem tests your ability to handle currency conversion using graph pathfinding (multiplicative weights) and implement a custom pagination algorithm that balances item distribution while respecting original ordering.
Coding & AlgorithmsOnsiteGraphsShortest PathGreedy - MercorMediumMachine Learning EngineerBuild a Candidate Search System
Design an end-to-end talent search and matching engine that combines semantic vector retrieval with structured filtering to handle unstructured resumes, ambiguous queries, and strict hiring constraints.
ML System DesignOnsiteml system designinformation retrievalnlp - MercorMediumMachine Learning EngineerCheck Whether Every Parcel Finds a Locker With Forward Overflow
Parcels arrive one at a time for a bank of numbered lockers, each requesting a preferred locker and overflowing to the next higher-numbered empty one if it's taken. Decide whether every parcel finds a locker. Tests precise rule-following and an efficient alternative to simulating forward scans one slot at a time.
Coding & AlgorithmsOnsiteunion-findsimulationarrays - MercorMediumSoftware EngineerCurrency Exchange Rate Between Two Currencies via Chained Conversions
Given a list of pairwise currency exchange rates such as USD to GBP at 0.77, compute the rate from a source currency to a target currency, converting through intermediate currencies and using rates in reverse where needed. It tests reasoning about chained conversions, unknown or unreachable currencies, and a clear time and space complexity analysis.
Coding & AlgorithmsOnsite - MercorMediumMachine Learning EngineerDesign Candidate Search And LLM Evaluation Tasks
Prepare for an MLE system design interview that combines candidate search, ranking, comparator reliability, and language-model fundamentals. The prompt covers retrieval, ranking feedback loops, top-k reasoning, transformer concepts, and decoding trade-offs without requiring proprietary hiring data.
ML System DesignOnsite - MercorMediumMachine Learning EngineerDesign Work Orchestration for Machine-Learning Data Pipelines
Design a resilient, multi-tenant orchestration engine tailored for machine learning pipelines that manages versioned DAGs, heterogeneous compute routing, data quality gates, and atomic dataset publication.
ML System DesignOnsiteML InfrastructureSystem DesignWorkflow Orchestration - MercorMediumMachine Learning EngineerDesign a DAG Pipeline Runner for Data-Labeling Jobs
Design a multi-tenant service that runs user-defined DAGs of automated steps (pre-processing, model pre-labeling, QA checks, exports), tracks every run, and survives crashes. Tests data modeling, separating the scheduler from workers, durable state, retries and idempotency, tenant fairness and observability.
System DesignOnsiteworkflow-orchestrationdistributed-systemsstate-machines - MercorMediumMachine Learning EngineerDesign a High-Demand Event Ticket Marketplace
Design an event ticketing platform capable of handling flash-sale spikes without overselling, featuring transactional seat holds, idempotent payment processing, and virtual queueing.
System DesignOnsitesystem-designdistributed-systemsconcurrency - MercorMediumMachine Learning EngineerDesign a workflow orchestration system that runs multi-step jobs reliably
A system design question asking you to build a workflow system where users define multi-step workflows with dependencies, start runs, and track progress. It tests data modeling, orchestration and worker architecture, durable state, retries and idempotency, fairness between tenants, scaling and observability.
System DesignOnsite - MercorMediumMachine Learning EngineerImplement a Referral Network
Design and implement an in-memory referral network as a directed acyclic graph (DAG) supporting cycle-safe edge insertion, depth-bounded reachability queries, and expected reward computation under geometric decay.
Coding & AlgorithmsOnsiteGraph AlgorithmsDAGBFS - MercorMediumMachine Learning EngineerReview a Compact GPT-Style Transformer Implementation
Assess and debug a compact decoder-only Transformer implementation. Candidates trace tensor dimensions through causal multi-head self-attention, identify flaws in next-token loss alignment and KV-cached generation, and establish equivalence between cached and uncached forward passes.
Machine LearningOnsiteTransformersPyTorchDeep Learning - MetaHardData ScientistAnalyze Algorithm's Impact on Diverse Demographics and Validate Causes
Analyze Algorithm's Impact on Diverse Demographics and Validate Causes evaluates metric design, causal reasoning, experiment setup, diagnostics, SQL/statistical checks, and recommendations in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Analytics & ExperimentationOnsite
Lyft
MathWorks
Mercor
Meta