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Coding & Algorithms 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 2851–2880 of 3276 results
- TikTokMediumMachine Learning EngineerFind length of longest common subsequence
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.
Coding & AlgorithmsTechnical ScreenDynamic ProgrammingStringsOptimization - 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 - TikTokHardSoftware EngineerFind longest substring with ≥k repeats
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.
Coding & AlgorithmsTechnical ScreenStringsSliding WindowTwo Pointers - 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 - TikTokEasySoftware EngineerFind start indices of anagram substrings
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.
Coding & AlgorithmsTechnical Screen - TikTokMediumSoftware EngineerFind the Longest Substring with at Most Two Distinct Characters
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.
Coding & AlgorithmsTechnical Screensliding-windowhash-tabletwo-pointers - TikTokMediumMachine Learning EngineerFix a BST with two misplaced keys
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.
Coding & AlgorithmsTechnical Screen - TikTokMediumSoftware EngineerFlatten object & Promise.all
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.
Coding & AlgorithmsTechnical Screen - TikTokHardMachine Learning EngineerGenerate all safe queen placements on board
This question evaluates algorithm design for constraint-satisfaction problems, testing skills in search, recursion, backtracking, combinatorics, and state-space pruning.
Coding & AlgorithmsTechnical Screen - 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 ScientistImplement K-means and run two iterations
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.
Coding & AlgorithmsTechnical Screen - TikTokMediumSoftware EngineerImplement O(1) randomized multiset
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.
Coding & AlgorithmsTechnical Screen - TikTokMediumSoftware EngineerImplement a match-3 board resolver
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.
Coding & AlgorithmsTechnical Screen - TikTokEasySoftware EngineerImplement an LRU cache
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.
Coding & AlgorithmsTechnical ScreenHash MapLinked ListDesign - TikTokMediumSoftware EngineerImplement binary tree in-order traversal
This question evaluates understanding of binary tree traversal, comparing recursive and iterative (explicit stack) implementations and their time and space complexity. Commonly asked in Coding & Algorithms interviews to assess both practical implementation and conceptual understanding of tree data structures, algorithmic trade-offs, and complexity analysis.
Coding & AlgorithmsTechnical Screen - TikTokHardMachine Learning EngineerImplement local maxima, bagging, and k-means
This problem tests your ability to implement a sliding window peak detector, a bootstrapping ensemble sampler, and a centroid-based clustering algorithm from scratch.
Coding & AlgorithmsOnline AssessmentAlgorithmsClusteringEnsemble Learning - TikTokMediumData ScientistImplement streaming SRM detector with late events
This question evaluates proficiency in stateful stream processing, statistical anomaly detection for sample ratio mismatch, and scalable system design concerns such as deduplication, late/out-of-order event handling, real-time aggregation, chi-square testing with Yates correction, bot-rate mitigation, sharding, and replay validation.
Coding & AlgorithmsHR Screen - TikTokMediumData ScientistMaximize Distinct Purchases Within Budget Constraints
This question evaluates understanding of selection and optimization under budget constraints, algorithmic efficiency, and the ability to implement correct logic for maximizing the number of distinct items purchased.
Coding & AlgorithmsOnline Assessment - TikTokMediumSoftware EngineerMaximize min+max of contiguous subarray
This question evaluates understanding of array algorithms and competency in identifying and reasoning about minimum and maximum values within contiguous subarrays, emphasizing extremal value handling.
Coding & AlgorithmsTechnical Screen - TikTokMediumData ScientistMaximize products bought under budget
This question evaluates algorithmic problem-solving skills including sorting, prefix-sum accumulation, binary search, greedy selection, careful tie-breaking for lexicographic order, and complexity analysis.
Coding & AlgorithmsOnline Assessment - 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 - TikTokMediumSoftware EngineerParse a nested list from a string
This problem tests your ability to parse recursive nested structures using stack-based iteration or recursion and string manipulation.
Coding & AlgorithmsTechnical ScreenRecursionStackParsing - TikTokMediumSoftware EngineerParse chemical formula with multipliers
Parse chemical formula with multipliers 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 & AlgorithmsTechnical Screen - 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 - TikTokMediumSoftware EngineerReconstruct a tree from two traversals
Reconstruct a tree from two traversals 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 & AlgorithmsTechnical Screen - 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 - TikTokMediumSoftware EngineerRestore Every Valid IP Address
Implement a backtracking algorithm to partition a digit string into four valid IPv4 octets, adhering to numerical range and leading-zero constraints.
Coding & AlgorithmsTechnical ScreenBacktrackingStringRecursion - 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 array and tree algorithm challenges
This question evaluates algorithmic problem-solving skills across array, heap, and tree data structures, testing competencies in duplicate handling, frequency aggregation, and balancing root-to-leaf path sums within the Coding & Algorithms domain.
Coding & AlgorithmsTechnical Screen - TikTokMediumSoftware EngineerSolve common string/DP/stack problems
This problem tests your ability to identify and implement an efficient solution for finding the longest substring that satisfies specific constraints, requiring a sliding window approach.
Coding & AlgorithmsTechnical ScreenSliding WindowHash MapStrings
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