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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 2161–2190 of 3276 results
- OptiverMediumQuantitative TraderSolve a Skyscraper puzzle efficiently
This question evaluates understanding of constraint satisfaction and combinatorial search, testing competency in modeling Latin-square domains with visibility constraints, pruning and uniqueness verification, and algorithmic complexity analysis.
Coding & AlgorithmsOnline Assessment - 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 - OptiverMediumSoftware EngineerValidate a Binary Tree Built from Directed Edges
This question evaluates understanding of tree and graph fundamentals including parent-child constraints, duplicate-edge detection, cycle detection, node-degree limits, and in-order traversal semantics.
Coding & AlgorithmsOnline Assessment - OracleMediumBackend EngineerAdd One to an Integer Stored as Digits Without ArrayList
This problem tests array manipulation skills and the ability to handle carry-over logic in fixed-size numerical representations.
Coding & AlgorithmsOnsiteArraysMathAlgorithms - 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 Islands and Return the Largest Island Size
Count four-connected islands and find the largest island using DFS or BFS, with correct visited-state handling and all-water behavior.
Coding & AlgorithmsOnsite - 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 - OracleMediumSoftware EngineerDetect whether a directed graph given as an edge list contains a cycle
A coding question that asks whether a directed graph, given as a node count and a list of edges, contains at least one directed cycle. It tests graph traversal on large inputs and careful handling of self-loops, duplicate edges, converging paths and disconnected components.
Coding & AlgorithmsOnsite - OracleMediumSoftware EngineerEnumerate Right-and-Down Paths Through a Binary Matrix
This problem tests your ability to explore paths in a grid using depth-first search (DFS) with backtracking while maintaining lexicographical output constraints.
Coding & AlgorithmsOnsiteDFSBacktrackingRecursion - OracleMediumSoftware EngineerFewest Coins for an Amount with Unlimited or Single-Use Coins
Return the fewest coins that add up exactly to an amount, first when every coin value can be reused without limit and then when each listed coin can be used at most once. An onsite coding problem that tests the difference between unlimited and single-use selection and the handling of amounts that cannot be formed.
Coding & AlgorithmsOnsite - OracleMediumSoftware EngineerFind Each Island's Maximum Height
This problem tests your ability to perform graph traversal (BFS/DFS) on a 2D grid while maintaining state across connected components.
Coding & AlgorithmsOnsiteGraphBFSDFS - OracleMediumSoftware EngineerFind shortest subarray meeting target sum
Find shortest subarray meeting target sum 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 & AlgorithmsOnsite - OracleMediumBackend EngineerFind the Best Profit from One Stock Trade
Tests array traversal, greedy state tracking, and achieving optimal O(n) time and O(1) space complexity for trade optimization.
Coding & AlgorithmsOnsiteArrayDynamic ProgrammingGreedy - OracleMediumSoftware EngineerFind the Lexicographically Maximum Suffix
This problem tests string manipulation, greedy algorithm design, and efficiency. It requires an O(n) solution to avoid Time Limit Exceeded errors on long strings, as naive O(n^2) comparisons will fail.
Coding & AlgorithmsOnsiteStringsTwo PointersGreedy - OracleMediumSoftware EngineerFind users with at least one valid session
This question evaluates the ability to parse and process event logs, pair signin/signout events per user, and handle unordered timestamps and per-user state with time-window constraints.
Coding & AlgorithmsOnsite - 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 EngineerLargest Island After Converting at Most One Water Cell to Land
Given a grid of land and water, convert at most one water cell to land and return the size of the largest island that can result. An onsite follow-up coding problem that tests connected-component sizing, joining neighboring islands without counting one twice, and efficiency on grids up to 500 by 500.
Coding & AlgorithmsOnsite - OracleMediumSoftware EngineerMaximize Movie Ratings Without Skipping Two in a Row
Find the maximum possible sum of a subsequence such that no two consecutive elements from the original array are omitted.
Coding & AlgorithmsOnsitedynamic-programmingarraysgreedy - OracleMediumSoftware EngineerMaximize Profit with One Stock Transaction
This problem tests the ability to find the optimal buy and sell points for a stock within a single transaction, focusing on an efficient O(n) single-pass approach.
Coding & AlgorithmsOnsiteArraysGreedyDynamic Programming - 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 EngineerMaximum stock trading profit with at most k buy-and-sell transactions
Given daily stock prices and a transaction limit k, compute the maximum profit achievable with at most k buy-then-sell trades while holding at most one share at a time. It tests generalizing a fixed-count trading problem, handling a k larger than the available profitable trades, and tracking state efficiently.
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