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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.
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Showing 1081–1110 of 1706 results
- OptiverHardSoftware EngineerDetect Currency Arbitrage After a Cycle Fee
You are given a matrix of positive currency exchange rates, where rates[i][j] units of currency j are received for one unit of currency i. Work through the function contract, boundary cases, correctness argument, and time and space complexity expected in a production-quality solution.
Coding & AlgorithmsTechnical Screen - OptiverMediumSoftware EngineerDetect currency arbitrage with costs
This question evaluates a candidate's competency in algorithmic problem modeling, graph-based cycle detection, and numerical reasoning about exchange rates and transaction costs.
Coding & AlgorithmsTechnical Screen - OptiverMediumSoftware EngineerMaintain Price Levels For A Single-Symbol Order Book
Design and implement a single-symbol limit order book that tracks individual orders and aggregates quantity by price level, supporting order additions, modifications, cancellations, and best price queries.
Coding & AlgorithmsTechnical Screenhash-tableheapdesign - OptiverMediumData ScientistMake Two Apple Piles Equal With Doubling Moves
This question evaluates algorithmic problem-solving and discrete-mathematics competencies, focusing on reasoning about state transitions, invariants, and number-theoretic constraints within the Coding & Algorithms domain for data scientist roles.
Coding & AlgorithmsTechnical Screen - OptiverMediumSoftware EngineerSolve three mini-game algorithm tasks
Solve three mini-game algorithm tasks 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 - OptiverEasyQuantitative ResearcherStone Pile Doubling Game: Can One Pile Be Emptied?
This question evaluates a candidate's algorithmic reasoning and discrete-mathematics skills, particularly understanding deterministic state transitions, invariants, and cycle detection in iterative processes.
Coding & AlgorithmsTechnical Screen - OptiverMediumSoftware EngineerThread-Safe Stock Inventory: Buy and Sell Without Overselling
This question evaluates understanding of concurrent programming, synchronization primitives, atomicity, and correctness of shared mutable state by requiring implementation of a thread-safe inventory that prevents overselling and preserves updates.
Coding & AlgorithmsTechnical Screen - OracleMediumSoftware EngineerApproximate a Square Root Across Values Above and Below One
This problem tests binary search on a continuous search space and the ability to handle numerical precision for numbers both greater than and less than one.
Coding & AlgorithmsTechnical ScreenBinary SearchMathNumerical Methods - OracleMediumSoftware EngineerCheck That a String of Three Bracket Types Is Properly Nested
Decide whether a string made of round, square and curly brackets is properly nested, meaning every closing bracket matches the most recently opened bracket of the same type and nothing is left open. Tests careful handling of nesting order, crossing pairs and unmatched brackets at either end.
Coding & AlgorithmsTechnical Screen - OracleMediumData ScientistCount Closed Islands
This problem tests your ability to navigate a 2D grid using graph traversal algorithms like DFS or BFS while identifying connected components that do not touch the grid boundaries.
Coding & AlgorithmsTechnical ScreenDFSBFSGraph - OracleMediumData ScientistCount Interior Islands After Flooding
This question evaluates understanding of grid-based graph traversal and connected-component detection, focusing on flood-fill logic and the treatment of boundary-connected regions in a binary grid.
Coding & AlgorithmsTechnical Screen - OracleMediumSoftware EngineerCount anagram-based replacements per phrase
This question evaluates skills in string processing, anagram grouping, frequency mapping, and combinatorial counting to determine how many phrase variations arise from permissible replacements in the Coding & Algorithms domain.
Coding & AlgorithmsTechnical Screen - OracleEasyData ScientistCount closed islands in a grid
This problem tests your ability to navigate a 2D grid using graph traversal algorithms like DFS or BFS while handling specific boundary constraints to identify closed regions.
Coding & AlgorithmsTechnical ScreenDFSBFSMatrix - OracleMediumSoftware EngineerDecide Whether a Parenthesis String With Star Wildcards Can Be Balanced
Decide whether a string of parentheses and stars can become a balanced parenthesis string when each star may independently act as an opening parenthesis, a closing parenthesis or an empty string. Tests reasoning over many possible replacements at once and edge cases with unmatched parentheses near either end.
Coding & AlgorithmsTechnical Screen - OracleEasySoftware EngineerDesign structure for first unique login user
This question evaluates a candidate's ability to design an efficient online data structure that maintains a stream of login events and supports constant-time updates and queries for the earliest user with exactly one login.
Coding & AlgorithmsTechnical Screen - OracleHardSoftware EngineerImplement Queue Operations Using Two Stacks
Implement queue enqueue, dequeue, and peek operations using exactly two LIFO stacks. The challenge tests transfer invariants, output ordering, amortized O(1) reasoning, large operation sequences, empty input, and compliance with restrictions against queue-like shortcuts.
Coding & AlgorithmsTechnical Screen - OracleHardSoftware EngineerImplement in-memory data structures and booking API
This problem tests your ability to design a thread-safe, in-memory booking system using efficient data structures to handle temporal queries and capacity management.
Coding & AlgorithmsTechnical ScreenHash MapConcurrencyAPI Design - OracleMediumSoftware EngineerMaximum of Fixed-Window Minimums
Tests the ability to compute sliding-window minima in linear time using a monotonic deque and determine the maximum value among those minima.
Coding & AlgorithmsTechnical Screensliding-windowmonotonic-queuedeque - OracleMediumSoftware EngineerRearrange an Integer Array into Its Next Lexicographic Arrangement
A coding problem that asks you to rearrange an integer array into the next lexicographically greater arrangement of its values, wrapping around to ascending order when the array is already the largest. It tests reasoning about lexicographic order, repeated values and complexity analysis.
Coding & AlgorithmsTechnical Screen - OracleMediumSoftware EngineerRepeatedly Delete Runs of k Adjacent Equal Characters from a String
Given a lowercase string and an integer k, repeatedly delete k adjacent equal characters, letting the remaining parts join and possibly form new runs, until no deletion is possible, then return what remains. It tests efficient simulation of cascading removals on strings of up to 100,000 characters.
Coding & AlgorithmsTechnical Screen - OracleMediumSoftware EngineerSum the Binary Numbers Spelled by Root-to-Leaf Paths in a 0/1 Tree
Given a binary tree of 0 and 1 bits in level-order form, return the sum of the binary numbers spelled by every root-to-leaf path, reading the root as the most significant bit. The problem tests tree traversal, carrying an accumulated value down each path, and parsing a level-order serialization correctly.
Coding & AlgorithmsTechnical Screen - OscarEasySoftware EngineerFind Clients Outside Provider Coverage
This problem tests spatial data processing and efficient set operations to identify gaps in service coverage between clients and providers based on distance and specialty requirements.
Coding & AlgorithmsTechnical ScreenAlgorithmsSpatialSet Operations - OtherEasyData ScientistCheck if a numeric string is divisible by 8
Determine whether a very large non-negative integer given as a decimal string is divisible by 8 without converting the whole string to an integer. The key insight is that only the last three digits matter (since 1000 is a multiple of 8), giving an O(1) check; a streaming modular-remainder approach is the O(n) alternative.
Coding & AlgorithmsTechnical Screen - OtherMediumBackend EngineerCompare Strings With Deletions
This question evaluates string processing and algorithmic optimization skills, specifically handling simulated deletions (backspace behavior) and performing comparisons under a strict auxiliary space constraint.
Coding & AlgorithmsTechnical Screen - OtherHardSoftware EngineerImplement a multi-button click detector
This question evaluates competency in real-time event stream processing, per-button state management, and timing-based classification of input events such as distinguishing single versus long presses.
Coding & AlgorithmsTechnical Screen - OtherMediumData ScientistImplement multiplication without using the multiplication operator
This question evaluates proficiency in bitwise arithmetic, integer overflow semantics, sign handling, and algorithmic efficiency for implementing multiplication without using multiplication or division operators.
Coding & AlgorithmsTechnical Screen - Otter.AiMediumSoftware EngineerEvaluate Arithmetic Expressions
This problem tests your ability to parse and evaluate a string representing a mathematical expression with basic operator precedence, typically requiring a stack-based approach or a recursive descent parser.
Coding & AlgorithmsTechnical ScreenStackString ParsingMath - Otter.AiMediumSoftware EngineerFixed-Width Text Display
This question tests a candidate's ability to implement greedy line-packing and space-distribution algorithms, core string manipulation skills evaluated in software engineering interviews. It assesses practical application of text layout logic, including handling edge cases like single-word lines and justified formatting with uneven space distribution.
Coding & AlgorithmsTechnical Screen - Otter.AiMediumSoftware EngineerImplement an Arithmetic Expression Evaluator
This problem tests your ability to parse and evaluate mathematical expressions containing non-negative integers, addition, subtraction, multiplication, and nested parentheses using a stack-based approach or recursion.
Coding & AlgorithmsTechnical ScreenStackParsingMath - Otter.AiMediumSoftware EngineerIn-Memory Key-Value Store with Nested Transactions
This problem tests the ability to implement a nested transactional key-value store using stack-based state management and scope shadowing.
Coding & AlgorithmsTechnical ScreenHash MapStackTransactions
Optiver
Oracle
Otter.Ai