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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 1–30 of 37 results
- Akuna CapitalMediumSoftware EngineerDesign two-user communications handler with exceptions
This question evaluates object-oriented design, state management, and custom exception handling skills for enforcing a single active communication pair and related invariants between two users.
Coding & AlgorithmsHR Screen - AmazonHardSoftware EngineerBuild an LRU Cache with a Hash Map and Linked List
This problem tests your ability to design a cache with O(1) time complexity for both get and put operations by combining a hash map with a doubly linked list.
Coding & AlgorithmsHR ScreenHash MapLinked ListDesign - AmazonHardSoftware EngineerReturn the Maximum of Every Sliding Window
This problem tests your ability to maintain a sliding window maximum using an efficient data structure like a deque to achieve linear time complexity.
Coding & AlgorithmsHR ScreenArraysSliding WindowDeque - ByteDanceHardBackend EngineerSolve Bracket Matching and Tree Width
This problem tests string manipulation and tree traversal techniques by requiring the validation of complex bracket sequences and the calculation of the maximum horizontal distance between nodes at the same level of a binary tree.
Coding & AlgorithmsHR ScreenStacksBFSTrees - Capital OneMediumSoftware EngineerGrid State After a Given Number of Days of Spoilage Spreading to Neighbors
A grid holds empty cells, fresh items and spoiled items, and each day spoilage spreads from every spoiled item to its edge-adjacent fresh neighbors. Given the grid and a number of days that may be very large, return the grid after exactly that many days. It tests simultaneous multi-source spreading, day-by-day timing, and unreachable cells.
Coding & AlgorithmsHR Screen - Capital OneMediumMachine Learning EngineerMaximize grid-path expression and count sawtooth subarrays
This multi-part question evaluates dynamic programming and state management for constrained grid traversal with left-to-right expression evaluation, alongside parity-based array analysis and combinatorial counting of contiguous subarrays.
Coding & AlgorithmsHR Screen - Capital OneMediumSoftware EngineerTop Two Teams by Points, Then Goal Difference, Then Goals Scored
Given parallel arrays of wins, draws, goals scored and goals conceded for each team, compute points as three per win plus one per draw and return the indices of the top two teams. Ties are broken by goal difference, then goals scored, then index, testing multi-key comparison and careful tie handling.
Coding & AlgorithmsHR Screen - CitadelMediumSoftware EngineerMaximize Earnings by Converting Days Off
Tests dynamic programming and state tracking to maximize daily earnings and consecutive work streak bonuses under a budget of schedule changes.
Coding & AlgorithmsHR Screendynamic-programmingalgorithmssliding-window - CitadelMediumSoftware EngineerMinimize Changes to Make Every Password Block Palindromic
Tests string manipulation and two-pointer techniques to determine the minimum character replacements needed to make independent fixed-length blocks palindromic.
Coding & AlgorithmsHR Screenstringstwo-pointersgreedy - CoinbaseMediumData ScientistDetect sequence rule and repair anomaly
This question evaluates a candidate's skill in sequence pattern recognition, algorithm design, complexity analysis, and robust integer arithmetic by requiring inference among arithmetic, alternating-difference, geometric, and Fibonacci-plus-constant models while tolerating at most one corrupted term under O(n) time and O(1) extra space constraints.
Coding & AlgorithmsHR Screen - DRWMediumSoftware EngineerLargest Number From a 1-and-2 Digit String With Even Counts of Each Digit
Given a string of 1s and 2s that represents a positive integer, delete characters so the remaining counts of both digits are even, keeping the original order, and return the largest number that can remain. The problem tests careful case analysis of which digit occurrences to remove and efficient string handling for inputs up to 200,000 characters.
Coding & AlgorithmsHR Screen - DRWHardSoftware EngineerMaximize a Digit Subsequence with Even Counts of Ones and Twos
Find the lexicographically/numerically largest subsequence of a string of '1's and '2's containing an even number of both digits in linear time.
Coding & AlgorithmsHR Screengreedystringssubsequences - DatabricksMediumSoftware EngineerSolve graph path, interval deletion, and robbery
This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Solve graph path, interval deletion, and robbery states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsHR Screen - Hudson River TradingEasySoftware EngineerMaximize Item Counts Under Suffix Budget Queries
Determine the maximum number of items that can be purchased from a suffix of an item array within a given budget for multiple independent queries.
Coding & AlgorithmsHR Screengreedysortingbinary-search - ImbueHardSoftware EngineerMax Score of an Alternating Left-Right Walk Over a Row of Signed Cells
A token walks a row of up to 50 signed cells, alternating right and left moves, and each move adds the sum of the cells it covers while the score must never drop below zero. Find the best score within up to 400 million moves, testing state design, the non-negative score constraint, and speed when the move count is huge.
Coding & AlgorithmsHR Screen - InstacartMediumSoftware EngineerEvaluate arithmetic expression using DFS
This question evaluates a candidate's understanding of expression parsing and evaluation using depth-first traversal, covering competencies in recursive descent or stack-based DFS, operator precedence, unary operators, and 64-bit integer division semantics with truncation toward zero.
Coding & AlgorithmsHR Screen - InstacartMediumSoftware EngineerOptimize file reading and expression DFS
This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Optimize file reading and expression DFS states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsHR Screen - InstacartMediumSoftware EngineerOptimize file reads for password validation
This question evaluates proficiency in on-disk file I/O, streaming algorithms, offline indexing for sublinear lookups, and system-level performance considerations for validating credentials in large files.
Coding & AlgorithmsHR Screen - MetaMediumSoftware EngineerSolve array merge and tree flattening problems
This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Solve array merge and tree flattening problems states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsHR Screen - MetaEasySoftware EngineerSolve four OA coding problems
This set of coding tasks evaluates fundamental skills in array manipulation, graph traversal, greedy strategy, and sequence analysis.
Coding & AlgorithmsHR ScreenArraysGreedyGraphs - MicrosoftMediumMachine Learning EngineerFind the Lowest Common Ancestor in a Binary Search Tree
This problem tests the ability to leverage the Binary Search Tree (BST) property to efficiently locate the Lowest Common Ancestor (LCA) of two nodes.
Coding & AlgorithmsHR ScreenBSTTreesRecursion - MicrosoftMediumMachine Learning EngineerFind the Lowest Common Ancestor in a Binary Tree
This problem tests tree traversal techniques and recursion logic to identify the deepest node that is an ancestor to two specified nodes in an arbitrary binary tree.
Coding & AlgorithmsHR ScreenTreesRecursionDFS - MicrosoftMediumMachine Learning EngineerImplement SFT Sample Packing
This problem tests your ability to efficiently pack variable-length sequences into fixed-length blocks for training, ensuring padding tokens do not influence the loss calculation.
Coding & AlgorithmsHR ScreenNLPData PreprocessingArrays - Morgan StanleyMediumData ScientistImplement Factorial and Squares
A Morgan Stanley data scientist HR-screen live-coding warm-up: implement Python `factorial(n)` (iteratively, then explain the recursive version) and `squares(n)` returning the squares of the first n integers. Evaluates clean Python, the iteration-vs-recursion trade-off, time and space complexity analysis, input validation, and edge cases like n = 0 and negative input.
Coding & AlgorithmsHR Screen - NVIDIAHardData ScientistDesign and explain robust web APIs for ML inference
This question evaluates a candidate's proficiency in designing HTTP REST APIs for ML inference, including API endpoints, versioning, idempotency, request/response schemas, authentication/authorization, rate limiting, observability, and backward-compatibility policies, and it falls under the Coding & Algorithms domain for a data scientist role.
Coding & AlgorithmsHR Screen - NVIDIAHardData ScientistImplement CUDA-tiled matrix multiplication and explain architecture
This question evaluates a candidate's competency in CUDA GPU programming, parallel algorithms, and performance engineering for FP32 matrix multiplication, covering tiling strategies, memory hierarchy (global/shared/register), synchronization, numerical precision, and occupancy/resource analysis.
Coding & AlgorithmsHR Screen - NVIDIAHardData ScientistOptimize CUDA GEMM with tiling and coalescing
This question evaluates proficiency in GPU programming and performance optimization, assessing understanding of the CUDA execution model, memory hierarchy and bank conflicts, occupancy limits, and practical kernel design concerns for single-precision GEMM including tiling, coalescing, vectorized memory accesses and benchmarking.
Coding & AlgorithmsHR Screen - NVIDIAHardData ScientistReverse linked lists, including k-group
This question evaluates understanding of linked list manipulation including pointer operations, in-place reversal techniques, recursion and stack-depth considerations, cycle detection, and time/space complexity analysis.
Coding & AlgorithmsHR Screen - OpenAIMediumSoftware EngineerImplement Three Research Coding Tasks
This problem tests fundamental understanding of numerical stability in probability, memory-efficient buffering, and greedy combinatorial optimization.
Coding & AlgorithmsHR ScreenNumerical StabilityDynamic ProgrammingStreaming Algorithms - RipplingHardSoftware EngineerSolve listed algorithm problems
This problem tests your ability to model exchange rates as a graph and use path-finding algorithms to detect profitable arbitrage opportunities.
Coding & AlgorithmsHR ScreenGraphsShortest PathBellman-Ford
Akuna Capital
Amazon
Capital One
Citadel
Coinbase
DRW
Databricks
Hudson River Trading
Instacart
Meta
Microsoft
Morgan Stanley
NVIDIA
OpenAI
Rippling