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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 3451–3480 of 3640 results
- UpstartEasyData ScientistCombine noisy thermometers; compute random-walk correlations
This question evaluates estimation and probabilistic reasoning skills, specifically the construction of unbiased estimators and variance-minimizing linear combinations for combining noisy measurements, together with computation and asymptotic characterization of correlations in a 2D simple random walk.
Statistics & MathOnsite - UpstartEasyData ScientistCompute decay, OLS, and classic probability results
This question evaluates probability and statistical modeling skills—probabilistic reasoning for exponential decay and the coupon-collector expectation, derivation of population OLS coefficients for simple linear models, simulation implementation, and conditional probability reasoning exemplified by the Monty Hall scenario.
Statistics & MathOnsite - UpstartMediumData ScientistDesign Algorithm for Longest Substring with K Distinct Characters
This question evaluates proficiency in string-processing and sliding-window algorithm patterns, assessing competency in designing efficient solutions and managing data structures to track distinct elements and reason about time and space complexity.
Coding & AlgorithmsOnsite - UpstartMediumData ScientistEstimate Family Proportions and Explain Regression Anomalies
Estimate Family Proportions and Explain Regression Anomalies 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 - UpstartMediumData ScientistEstimate and Derive Regression Coefficient for X on y
Estimate and Derive Regression Coefficient for X on y 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 - UpstartEasyData ScientistExplain L1 vs L2 and ridge vs lasso
This question evaluates understanding of regularization techniques in Machine Learning—specifically distinctions between L1 and L2 norms and their instantiation as Lasso and Ridge regression—covering effects on objective functions, parameter sparsity, geometric intuitions, handling of correlated features, and the role of feature scaling.
Machine LearningOnsite - UpstartEasyData ScientistImplement factorial and count trailing zeros
This question evaluates understanding of factorial computation and algorithmic techniques, including iterative versus recursive approaches, handling large integers and recursion constraints, and efficient counting of trailing zeros via number-theoretic reasoning.
Coding & AlgorithmsOnsite - UpstartMediumData ScientistLeverage Existing Model for Low Credit Score Applicants
Leverage Existing Model for Low Credit Score Applicants evaluates core ML concepts, assumptions, math intuition, training/evaluation trade-offs, and practical failure modes in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Machine LearningOnsite - UpstartMediumData ScientistSolve core probability/statistics mini-problems
Category: Statistics & Math; this prompt evaluates core probability and statistical concepts — exponential decay and discrete survival counts, Bayesian updating, properties of population OLS coefficients, conditional-probability reasoning exemplified by Monty Hall, the coupon-collector expected time, and the conceptual distinction between likelihood and probability — relevant for Data Scientist roles. It is commonly asked because it probes foundational distributional intuition, independence and conditional inference, and expectation/estimation at an introductory-to-intermediate theoretical level that underpins applied modeling and experimental interpretation.
Statistics & MathOnsite - ValonMediumSoftware EngineerBuild a staged banking service: ATM cash, statements, transfers, fees, slow transfers
A staged, roughly two-hour coding exercise to build a banking service: ATM balance, deposits and withdrawals, per-account statements that include failed transactions, instant transfers, external transfers that charge a fee, and slow transfers that hold funds until they arrive. It tests exact money handling, ledger design and extensible code.
Software Engineering FundamentalsOnsite - ValonMediumBackend EngineerDesign Correct Stateful Services for Irregular Financial Events
A systems-design interview about correct stateful processing for sparse records, out-of-order loan events, investor payment allocation, and authenticated APIs. It emphasizes idempotency, ledgers, exact arithmetic, recovery, and auditability.
System DesignOnsite - ValonMediumSoftware EngineerDesign a Loan System with Borrower Repayments and Periodic Investor Payouts
System design question about a loan system in which borrowers make repayments and the investors who own the loans are paid on a schedule. It tests loan and ownership modeling, repayment allocation, exact ledger accounting, idempotent payout runs, cent-level splitting among investors, and handling of payments reversed after a payout.
System DesignOnsite - VantaMediumSoftware EngineerDeduplicate a File Exactly When Distinct Lines Exceed Memory
Design exact external-memory global line deduplication with sorting or partitioning, full equality checks, and optional first-occurrence order preservation.
Software Engineering FundamentalsOnsite - VantaMediumSoftware EngineerDescribe Something New You Learned Recently
Tests a candidate's intellectual curiosity, self-directed learning ability, technical self-awareness, and capability to translate newly acquired knowledge into practical engineering impact.
Behavioral & LeadershipOnsiteBehavioralContinuous LearningGrowth Mindset - VantaMediumSoftware EngineerDesign a DAU/MAU metrics system
A Vanta software-engineer system-design interview question: design a scalable pipeline to compute and serve DAU and MAU engagement metrics for a large consumer app. It tests event ingestion, identity and de-duplication, exact vs. approximate distinct counting (HyperLogLog/bitmaps), handling of time zones and late/out-of-order events, streaming-vs-batch correctness, dashboard serving, and monitoring/privacy.
System DesignOnsite - VantaMediumSoftware EngineerExplain Team Impact and Executive Collaboration
Tests your ability to identify systemic engineering improvements beyond assigned tasks and collaborate effectively with senior leadership to enact consequential change. It evaluates influence without formal authority, audience-appropriate risk communication, and durable adoption.
Behavioral & LeadershipOnsiteBehavioralLeadershipStakeholder Management - VantaMediumSoftware EngineerImplement Adjacent-Line Uniq
Implement a Unix-style adjacent-line deduplication function that groups consecutive identical lines, supports case-insensitive matching, and filters output based on run counts in linear time.
Coding & AlgorithmsOnsitetwo-pointersstringsimulation - VantaEasySoftware EngineerImplement a Unique Lines Command
Implement a streaming generator that mimics the Unix `uniq` command by collapsing consecutive duplicate lines with options for counting and case-insensitivity.
Coding & AlgorithmsOnsiteStreamingString ProcessingFile I/O - VantaMediumSoftware EngineerMeasure Most-Viewed URLs and Subscription Conversion Rates
Design web metrics around precise view, URL, identity, cohort, and conversion definitions with durable aggregation and late-event handling.
System DesignOnsite - VantaMediumSoftware EngineerOrder Classes by Prerequisites with Recursive DFS
Build a deterministic prerequisite ordering with recursive depth-first search. Handle disconnected classes and detect dependency cycles by tracking both active and completed nodes.
Coding & AlgorithmsOnsite - VantaMediumSoftware EngineerReview and Debug an AI Chatbot
Design an end-to-end debugging, observability, and evaluation architecture for a multi-tenant enterprise AI compliance chatbot experiencing hallucinations, latency spikes, and policy violations.
ML System DesignOnsiteLLM ObservabilityRAGData Privacy - Veeva SystemsMediumSoftware EngineerCompute build order from dependencies
Compute build order from dependencies 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 - VercelMediumSoftware EngineerDesign Collaborative Document Editing
This question tests your ability to design a distributed system capable of handling concurrent, low-latency document edits using conflict resolution strategies.
System DesignOnsiteWebSocketsCRDTConcurrency - VercelEasySoftware EngineerGroup Tree Nodes into Layers from the Leaves Up to the Root
Given a rooted tree described as an undirected edge list, return its nodes in layers from the leaves up to the root, where each node sits one layer above its highest child and each layer is sorted. It tests rooting a tree from a graph, bottom-up ordering, and handling very deep, path-shaped trees.
Coding & AlgorithmsOnsite - VercelMediumSoftware EngineerSearch Recorded Metrics by Name, Tags, and Recency
Design an in-memory metric storage and querying system that allows recording time-series metrics with key-value tags and retrieving the most recent matches filtered by name and tags.
Coding & AlgorithmsOnsitedata-structureshash-tablesorting - VercelEasySoftware EngineerSystem Design: A Short-Link Service That Redirects in Milliseconds
Design a service that turns long URLs into short, shareable links and redirects visitors to the original destination with minimal latency. Tests capacity estimation, collision-free code generation under concurrent writes, a read-optimized data model, and how to scale and harden the redirect path.
System DesignOnsitesystem-designcachingdata-modeling - VerkadaMediumFrontend EngineerBuild a React dashboard with filters
This problem tests your ability to build a modular React dashboard that handles state synchronization, efficient list filtering, and semantic UI structure.
Software Engineering FundamentalsOnsiteReactFrontendState Management - VerkadaMediumSoftware EngineerFind user who can access every camera
This problem tests your ability to model hierarchical access control systems as a directed graph and determine reachability using graph traversal techniques like BFS or DFS.
Coding & AlgorithmsOnsiteGraphsBFS/DFSReachability - VerkadaMediumSoftware EngineerImplement LRU and LFU caches
This question evaluates understanding of cache eviction policies and data structure design, focusing on LRU and LFU semantics and the ability to support O(1) average-time get/put operations.
Coding & AlgorithmsOnsite - VerkadaMediumFrontend EngineerImplement a recency cache and min-coins DP
This problem tests your ability to combine a Least Recently Used (LRU) cache mechanism with a dynamic programming approach for optimization.
Coding & AlgorithmsOnsiteHash MapDoubly Linked ListDynamic Programming
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