TikTok interview questions

Showing 91–120 of 176 results

• Explain a challenging project end-to-endMedium

  This question evaluates project ownership, cross-functional leadership, technical decision-making, and metrics-driven execution within a software engineering Behavioral & Leadership interview, focusing on competencies such as stakeholder coordination, data-informed trade-offs, and operational reliability.

  TikTokSoftware EngineerBehavioral & LeadershipTechnical Screen
• Explain and tune XGBoost; prevent overfittingHard

  This question evaluates understanding of XGBoost tree-boosting internals, hyperparameter impacts on bias/variance/training time, strategies for imbalanced binary classification and leakage-aware validation, post-training calibration, and interpretability for tabular fraud detection.

  TikTokData ScientistMachine LearningTechnical Screen
• Explain gap and project contributionsMedium

  This question evaluates a candidate's ability to explain employment gaps and provide a project deep-dive demonstrating ownership, technical decision-making, measurable impact, and clear delineation of personal contributions, testing communication, accountability, and system design competencies.

  TikTokSoftware EngineerBehavioral & LeadershipTechnical Screen
• Explain motivation for QA and career goalsEasy

  This question evaluates a candidate's career motivation, communication and leadership competencies alongside technical troubleshooting and QA/testing role fit by probing short- and mid‑term goals, reasons for graduate study, and rationale for pursuing QA versus other engineering tracks.

  TikTokSoftware EngineerBehavioral & LeadershipTechnical Screen
• Explain your VLM project end-to-endMedium

  This question evaluates proficiency in vision-language model engineering, including model architecture (vision encoder, language model, fusion), data curation and distribution, training recipes, evaluation metrics, inference latency, and limitations analysis within the Machine Learning domain of multimodal/Vision-Language models.

  TikTokMachine Learning EngineerMachine LearningTechnical Screen
• Explain your most impactful project trade-offsMedium

  This question evaluates a data scientist's leadership, stakeholder management, quantitative impact measurement, trade-off analysis, risk mitigation, and conflict-resolution skills within end-to-end project work.

  TikTokData ScientistBehavioral & LeadershipTechnical Screen
• Find a valid course order from prerequisitesMedium

  This problem tests your ability to model dependencies as a directed graph and determine a valid sequence using topological sorting (Kahn's algorithm or DFS).

  TikTokSoftware EngineerCoding & AlgorithmsTechnical Screen
• Find and count target-sum subarraysMedium

  Find and count target-sum subarrays 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.

  TikTokMachine Learning EngineerCoding & AlgorithmsTechnical Screen
• Find first and last index of targetEasy

  This question evaluates mastery of searching algorithms and algorithmic complexity analysis, particularly the ability to locate boundary positions within a sorted array.

  TikTokSoftware EngineerCoding & AlgorithmsTechnical Screen
• Find kth smallest in sorted 2D matrixMedium

  This question evaluates algorithmic problem-solving and data-structure reasoning, focusing on order statistics and operations on a row- and column-sorted matrix within the Coding & Algorithms domain.

  TikTokSoftware EngineerCoding & AlgorithmsTechnical Screen
• Find length of longest common subsequenceMedium

  This problem tests your ability to identify overlapping subproblems and optimal substructure by implementing a dynamic programming solution to find the length of the Longest Common Subsequence (LCS) between two strings.

  TikTokMachine Learning EngineerCoding & AlgorithmsTechnical Screen
• Find longest common subsequence lengthMedium

  This question tests the ability to solve the Longest Common Subsequence (LCS) problem using dynamic programming, specifically focusing on building a 2D state table.

  TikTokSoftware EngineerCoding & AlgorithmsOnsite
• Find longest substring with ≥k repeatsHard

  This problem tests your ability to use the sliding window technique combined with frequency maps to find the longest substring containing characters that each appear at least k times.

  TikTokSoftware EngineerCoding & AlgorithmsTechnical Screen
• Find longest substring without repeating charactersMedium

  This question evaluates proficiency in string processing, duplicate-detection using appropriate data structures, and algorithmic complexity analysis within the Coding & Algorithms domain.

  TikTokMachine Learning EngineerCoding & AlgorithmsOnsite
• Find start indices of anagram substringsEasy

  This question evaluates proficiency in string processing, frequency-based pattern matching, and algorithmic efficiency under length constraints, testing the ability to reason about time and space trade-offs for substring searches.

  TikTokSoftware EngineerCoding & AlgorithmsTechnical Screen
• Find the Longest Substring with at Most Two Distinct CharactersMedium

  Tests the ability to use the sliding window technique combined with a hash map to maintain a dynamic character set and determine the maximum length of a valid substring in linear time.

  TikTokSoftware EngineerCoding & AlgorithmsTechnical Screen
• Find top-paid employee per departmentEasy

  This question evaluates a candidate's competency in SQL data manipulation, including aggregation, ranking, handling of duplicate and historical rows, tie semantics, and temporal data interpretation when determining the top-paid employee per department.

  TikTokData ScientistData Manipulation (SQL/Python)Technical Screen
• Fix a BST with two misplaced keysMedium

  This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Fix a BST with two misplaced keys states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

  TikTokMachine Learning EngineerCoding & AlgorithmsTechnical Screen
• Flatten object & Promise.allMedium

  This question evaluates proficiency in JavaScript data manipulation and asynchronous programming, testing competencies in transforming nested objects into single-level key paths and reproducing Promise.all semantics.

  TikTokSoftware EngineerCoding & AlgorithmsTechnical Screen
• Generate all safe queen placements on boardHard

  This question evaluates algorithm design for constraint-satisfaction problems, testing skills in search, recursion, backtracking, combinatorics, and state-space pruning.

  TikTokMachine Learning EngineerCoding & AlgorithmsTechnical Screen
• Give a Technical Research-Project Deep DiveEasy

  Tests your ability to communicate complex technical research clearly, delineate your specific personal contributions, explain rigorous experimental design, and critically evaluate limitations and next steps.

  TikTokSoftware EngineerBehavioral & LeadershipTechnical Screen
• Handle disorganized interview logisticsMedium

  This question evaluates a candidate's communication, initiative, and stakeholder-management competencies in coordinating interview logistics for a Software Engineer role.

  TikTokSoftware EngineerBehavioral & LeadershipTechnical Screen
• How do you choose a classification threshold?Easy

  This question evaluates a data scientist's competency in binary classification threshold selection, end-to-end ML pipeline design, model evaluation, and operational trade-offs including class imbalance, asymmetric error costs, and limited escalation capacity, within the Machine Learning domain of model evaluation and deployment.

  TikTokData ScientistMachine LearningTechnical Screen
• How would you measure misinformation impact and recommendation bias?Easy

  This question tests the ability to design an evaluation framework for identifying algorithmic bias and measuring the reach of misinformation within a content recommendation system.

  TikTokData ScientistAnalytics & ExperimentationTechnical Screen
• Identify Repeat Advertisers from Consecutive WeeksMedium

  This question evaluates a candidate's proficiency in manipulating relational data to identify recurring entities across consecutive time periods, focusing on SQL/Python data manipulation and temporal comparison of records.

  TikTokData ScientistData Manipulation (SQL/Python)Technical Screen
• Implement Hash Map OperationsMedium

  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.

  TikTokBackend Software EngineerCoding & AlgorithmsOnsite
• Implement K-means and run two iterationsMedium

  This question evaluates understanding of k-means clustering concepts (k-means++ initialization, Lloyd iterations, and SSE) and proficiency in numerical implementation and vectorized array operations.

  TikTokData ScientistCoding & AlgorithmsTechnical Screen
• Implement O(1) randomized multisetMedium

  Implement O(1) randomized multiset 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.

  TikTokSoftware EngineerCoding & AlgorithmsTechnical Screen
• Implement a match-3 board resolverMedium

  TikTok software-engineer technical-screen coding question: implement a match-3 board resolver over an m×n grid. Repeatedly remove connected horizontal/vertical runs of three or more equal cells, apply gravity so survivors fall and blanks rise to the top, cascade until the board is stable, and return the final board plus the total cells removed. It tests grid simulation, run detection via linear scans, per-column gravity, termination reasoning, and time/space complexity analysis.

  TikTokSoftware EngineerCoding & AlgorithmsTechnical Screen
• Implement an LRU cacheEasy

  This question tests the ability to implement a Least Recently Used (LRU) cache using a combination of a hash map and a doubly linked list to achieve constant time complexity for core operations.

  TikTokSoftware EngineerCoding & AlgorithmsTechnical Screen