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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 3301–3330 of 3640 results
- ThumbtackHardData ScientistLead XFN decision under tight timeline
This question evaluates cross-functional leadership, stakeholder alignment, rapid decision-making under time pressure, data triage and technical judgment, executive communication, and risk management skills.
Behavioral & LeadershipOnsite - ThumbtackMediumData ScientistTest regional response-rate differences rigorously
This question evaluates applied statistical modeling and causal-inference competencies, including adjustment for confounding, analysis of proportion/count outcomes, variance estimation under clustering, multiple-comparison control, diagnostic detection of Simpson’s paradox, and clear effect-size reporting; it is categorized under Statistics & Math and emphasizes practical application with necessary conceptual understanding. Such problems are commonly asked to assess the ability to justify and interpret comparative analyses that account for covariate mix, temporal structure, and multiple-testing concerns, and this summary is in English.
Statistics & MathOnsite - TikTokHardData ScientistAct when A/B result is not significant
This question evaluates a candidate's competency in experimental design and statistical decision-making, covering sample size calculation, variance-reduction methods, interpretation of non-significant A/B results, multiplicity control, and sequential/Bayesian decision frameworks.
Statistics & MathOnsite - TikTokMediumData ScientistBalance Customer Satisfaction with Fraud Prevention: Key Metrics to Track
Evaluates risk-decisioning trade-offs between customer experience and fraud prevention in payment products. Strong answers cover cost-sensitive thresholds, false declines, fraud loss, experimentation, monitoring, and delayed labels.
Analytics & ExperimentationOnsite - TikTokMediumData ScientistCompute Averages of Unique Numbers in Dictionary Lists
This question evaluates data manipulation and aggregation skills, focusing on handling duplicate values within collections and computing numerical summaries of list data.
Coding & AlgorithmsOnsite - TikTokMediumData ScientistCompute CTR drop with exclusions
This question evaluates a candidate's ability to compute time-windowed click-through rates using SQL aggregations, joins, filters and data-cleaning (excluding suspicious ads) while handling edge cases such as missing days, minimum-impression thresholds, division-by-zero, and integer-division pitfalls.
Data Manipulation (SQL/Python)Onsite - TikTokHardData ScientistControl confounding in observational ad lift
This question evaluates mastery of observational causal inference for ATE estimation, covering causal DAGs and identification, pre-treatment adjustment, propensity-score and inverse-probability/doubly-robust estimation, diagnostic checks, sensitivity analysis for unobserved confounding, and variance/uncertainty quantification in the context of ad exposure data. It is commonly asked because real-world advertising analyses cannot rely on randomization and interviewers need assurance of both conceptual understanding of identification assumptions and practical application of estimation and diagnostic techniques; the category is Statistics & Math and the level of abstraction spans conceptual reasoning and applied implementation.
Statistics & MathOnsite - TikTokHardData ScientistDesign A/B Test for Cost-Per-Conversion Efficiency Analysis
Design A/B Test for Cost-Per-Conversion Efficiency Analysis 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 - TikTokHardData ScientistDesign Real-Time Credit Card Fraud Detection System
Evaluates real-time credit-card fraud detection system design under latency, drift, and asymmetric costs. Strong answers cover data, delayed labels, features, models, serving architecture, monitoring, retraining, and thresholding.
Machine LearningOnsite - TikTokMediumData ScientistDesign a creator posting-frequency experiment
This problem tests the ability to design a controlled experiment while accounting for network interference, non-compliance, and selection bias in a two-sided platform.
Analytics & ExperimentationOnsiteExperimentationA/B TestingCausal Inference - TikTokMediumMachine Learning EngineerDesign a model to choose dynamic K
This question evaluates a candidate's competency in ML system design and decision-focused modeling for recommender pipelines, focusing on retrieval-ranking trade-offs, latency and compute cost constraints, and dynamic per-request selection of K.
ML System DesignOnsite - TikTokEasyData ScientistDesign multimodal deployment under compute limits
This question evaluates competency in Machine Learning systems engineering for a Data Scientist role, covering multimodal model deployment and inference optimization, scalable retrieval (ANN and hybrid search), generalization and regularization concepts (overfitting, dropout), normalization methods, and RLHF, emphasizing both theoretical principles and engineering feasibility. It is commonly asked to assess reasoning about trade-offs between quality, latency, and cost in resource-constrained environments, validation via offline/online metrics, and the ability to bridge conceptual understanding with practical deployment and system-level design considerations.
Machine LearningOnsite - TikTokHardProduct ManagerDetecting and Mitigating Cheating in Games
Practice designing an anti-cheat product strategy for competitive online games with real-time matches, ranked leaderboards, and an in-game economy. The solution covers detection signals, streaming and batch pipelines, modeling approaches, prevention, graduated enforcement, appeals, false-positive recovery, and trust metrics.
Product Design & StrategyOnsite - TikTokMediumMachine Learning EngineerDetermine frog reachability across stones
This question evaluates dynamic programming, state-space reachability, and constrained transition reasoning, along with skills in hash-based memoization and time/space complexity analysis.
Coding & AlgorithmsOnsite - TikTokMediumData ScientistDiagnose Search Issues with Relevant Metrics and Solutions
Evaluates diagnosis of brand-name search relevance and safety issues using analytics and experimentation. Strong answers define relevance, satisfaction, and harmful-content metrics, find root causes, and validate fixes offline and online.
Analytics & ExperimentationOnsite - TikTokHardData ScientistDiagnose metric drop in Ads Manager
This question evaluates a Data Scientist's competency in operational analytics, metric integrity, root-cause analysis, and experiment interpretation, covering concepts such as logging latency, sample ratio assessment, and product instrumentation awareness.
Analytics & ExperimentationOnsite - TikTokMediumProduct ManagerDigital Marketing Campaign ROI Analysis
Practice allocating budget between two TikTok mobile-game ad creatives using funnel and ROI analysis. The solution covers CTR, CVR, IPM, CPI, ARPU, ROAS, marginal return, creative fatigue, growth headroom, long-term LTV, confidence, and exploration-versus-exploitation decisions.
Product / Decision MakingOnsite - TikTokHardSoftware EngineerExplain Your System Architecture
Explain Your System Architecture evaluates requirements, scale assumptions, API/data design, architecture, trade-offs, failure modes, and rollout in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
System DesignOnsite - TikTokMediumBackend Software EngineerExplain a Difficult Project and Its Scaling Decisions
Practice explaining a difficult engineering project through ownership, technology choices, scaling constraints, and measured trade-offs. The model answer uses a clearly hypothetical ingestion service to show how to discuss alternatives, bottlenecks, rollout evidence, and lessons without exposing private project details.
Behavioral & LeadershipOnsite - TikTokMediumSoftware EngineerFind longest common subsequence length
This question tests the ability to solve the Longest Common Subsequence (LCS) problem using dynamic programming, specifically focusing on building a 2D state table.
Coding & AlgorithmsOnsiteDynamic ProgrammingStringsAlgorithms - TikTokMediumMachine Learning EngineerFind longest substring without repeating characters
This question evaluates proficiency in string processing, duplicate-detection using appropriate data structures, and algorithmic complexity analysis within the Coding & Algorithms domain.
Coding & AlgorithmsOnsite - TikTokMediumBackend Software EngineerImplement Hash Map Operations
Build a hash map behind a deterministic operation stream with insertion, replacement, lookup, removal, and missing-key behavior. The specification avoids built-in map storage and fixes return ordering and value bounds for a future portable console implementation.
Coding & AlgorithmsOnsite - TikTokMediumData ScientistImprove TikTok's Algorithm for Diverse Content Discovery
Evaluates product feedback and experiment design for improving content discovery in TikTok-style feeds. Strong answers propose specific improvements, justify impact, define metrics, and plan experiments with guardrails.
Analytics & ExperimentationOnsite - TikTokHardData ScientistMeasure Billboard Campaign Effectiveness and Engagement Quantification
Evaluates offline marketing measurement for a billboard campaign, including how to define attributable engagement, estimate exposed population, and forecast incremental traffic, sign-ups, retention, revenue, and ROI. Strong answers use geo-lift, matched markets, or synthetic controls rather than direct attribution alone.
Analytics & ExperimentationOnsite - TikTokMediumData ScientistOptimize Station Sequence for Maximum Car Output in Simulation
This question evaluates a candidate's skills in scheduling and throughput optimization, including queue management and simulation-based performance analysis within constrained buffering and station sequencing.
Coding & AlgorithmsOnsite - TikTokMediumBackend Software EngineerProcess LRU Cache Operations
Implement an LRU cache through a deterministic stream of put and get operations, including updates, misses, and eviction order. The prompt defines an exact portable function contract and examples suitable for a later four-language console handoff.
Coding & AlgorithmsOnsite - TikTokHardSoftware EngineerRemove the Fewest Overlapping Intervals
Tests greedy interval scheduling and sorting techniques to find the minimum number of intervals to remove so that no remaining intervals overlap.
Coding & AlgorithmsOnsiteGreedySortingIntervals - TikTokMediumData ScientistResolve Stakeholder Conflicts: Actions and Outcomes Explained
Evaluates behavioral stakeholder-conflict storytelling for data scientists delivering products or experiments. Strong answers use STAR, show empathy, structure trade-offs, drive decisions, and quantify outcomes.
Behavioral & LeadershipOnsite - TikTokHardSoftware EngineerSchedule Seller Tasks with Tier-Weighted Round Robin
Design a task scheduler that dispenses seller tasks using tier-weighted round-robin across sellers while strictly preserving per-seller priority and FIFO order.
Coding & AlgorithmsOnsiteQueueHeapDesign - TikTokMediumSoftware EngineerSolve intervals and distinct islands
This question evaluates skills in interval manipulation and identification of distinct connected components in grids, testing competencies in data structure usage, algorithmic reasoning, and spatial pattern recognition within the Coding & Algorithms domain.
Coding & AlgorithmsOnsite
Thumbtack
TikTok