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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 811–840 of 1080 results
- PinterestMediumSoftware EngineerImplement stream line reader and settle balances
This question evaluates streaming I/O and buffered string-processing competency for Part 1 and transaction netting with balance computation for Part 2, covering skills in memory-bounded parsing, data-structure bookkeeping, and algorithmic flow reasoning.
Coding & AlgorithmsOnsite - PinterestMediumSoftware EngineerImplement string-based big integer multiplication
Implement multiplyStrings(a, b) to multiply two non-negative integers given as decimal strings, returning the product as a string without any big-integer or arbitrary-precision library. The solution covers grade-school O(n*m) long multiplication with linear memory, the Karatsuba and FFT/NTT scaling alternatives, correct carry and leading/trailing-zero handling, and a full edge-case test plan.
Coding & AlgorithmsOnsite - PinterestHardMachine Learning EngineerImplement trie-based autocomplete
This problem tests your ability to implement a space-efficient Trie data structure capable of storing strings along with associated weights to return top-k suggestions for a given prefix.
Coding & AlgorithmsOnsiteTrieData StructuresStrings - PinterestMediumSoftware EngineerInsert Operators to Reach a Target
Tests backtracking with operator precedence handling and operand formatting to construct all valid arithmetic expressions evaluating to a target value.
Coding & AlgorithmsOnsitebacktrackingrecursionstring - PinterestHardSoftware EngineerList All Plus/Times Expressions Reaching a Target Under Operator Precedence
Tests backtracking and state tracking with operator precedence to evaluate and enumerate arithmetic expressions using addition and multiplication.
Coding & AlgorithmsOnsiteBacktrackingRecursionMath - PinterestMediumData ScientistMaximize Non-Overlapping Task Scheduling Efficiency
This question evaluates understanding of interval scheduling and resource optimization, focusing on reasoning about time intervals and conflict-free selection of tasks.
Coding & AlgorithmsOnsite - PinterestMediumSoftware EngineerMinimum Transfers Between Pin Boards
Tests breadth-first search and graph modeling skills by finding the shortest path across overlapping collections without constructing a dense graph between every pair.
Coding & AlgorithmsOnsiteBFSGraphHash Map - PinterestMediumSoftware EngineerReconstruct an Itinerary from Flight Tickets
Tests graph modeling, depth-first search (DFS), and Hierholzer's algorithm to construct an Eulerian path with lexicographical tie-breaking.
Coding & AlgorithmsOnsiteGraphDFSEulerian Path - PinterestMediumSoftware EngineerReconstruct route from unordered travel tickets
This problem tests your ability to model a graph where each edge represents a transition, requiring you to find a valid linear sequence that visits every node exactly once.
Coding & AlgorithmsOnsiteGraphsHash MapLinked List - PinterestMediumSoftware EngineerSettle debts with minimal transactions
Pinterest software-engineer onsite coding question: given a list of debts as (debtor, creditor, amount) triples, return settlement transfers that clear every net balance using the minimum number of transactions. It tests reducing to net balances, recognizing the problem is NP-hard, backtracking with pruning to find the optimum for small N, and a heap-based greedy heuristic plus correctness and time/space complexity analysis for large, skewed debt graphs.
Coding & AlgorithmsOnsite - PinterestMediumMachine Learning EngineerSolve Expression and Tree-List Problems
This problem tests recursive backtracking for expression generation and pointer manipulation for in-place tree-to-linked-list conversion.
Coding & AlgorithmsOnsiteBacktrackingTreesLinked Lists - PinterestMediumSoftware EngineerSolve Four Interview Coding Problems
This set tests proficiency in graph algorithms, binary search on sorted data, grid simulations, and custom data structure design for real-time leaderboards.
Coding & AlgorithmsOnsiteGraphsBinary SearchSimulation - PinterestMediumMachine Learning EngineerSolve five hard algorithm problems
This problem tests your ability to optimize range-based operations using a difference array or prefix sum strategy and demonstrates your skill in balancing computational efficiency with memory constraints.
Coding & AlgorithmsOnsiteArraysPrefix SumDifference Array - PinterestMediumMachine Learning EngineerSolve prefix, array, and string problems
This problem tests your ability to efficiently manage prefix-based string searching using a Trie data structure, specifically focusing on handling wildcard character matching.
Coding & AlgorithmsOnsiteTrieStringRecursion - PinterestMediumSoftware EngineerSolve set equality and ad log top‑K
This multi-part question evaluates set and multiset operations, frequency counting, top-K computation over time windows, sliding-window and streaming data structures, and character-multiset matching for string construction within the coding & algorithms domain.
Coding & AlgorithmsOnsite - PinterestHardMachine Learning EngineerSupport room moves and query top-k fastest
This problem tests your ability to design a data structure that efficiently manages room assignments and retrieves the top-k rooms based on a primary priority (number of people) and a secondary priority (earliest arrival time).
Coding & AlgorithmsOnsiteData StructuresHeapHash Map - PitchbookEasySoftware EngineerImplement Euclidean distance and k-nearest neighbors
This question evaluates understanding of Euclidean distance metrics, vector arithmetic, and nearest-neighbor retrieval, testing implementation skills for computing distances and selecting the k closest points.
Coding & AlgorithmsOnsite - PurestorageMediumSoftware EngineerDetermine whether points form squares
This question evaluates computational geometry, combinatorial counting, and algorithmic optimization skills by requiring validation of a non-degenerate square from four 2D integer points and counting distinct squares in a larger point set, and it falls under the Coding & Algorithms category.
Coding & AlgorithmsOnsite - RampMediumSoftware EngineerSpreadsheet String Concatenation with Dependent Cells
Build a fixed-grid string spreadsheet with concatenation formulas, dependency updates, repeated references, and read-time circular-reference errors.
Coding & AlgorithmsOnsite - RampHardSoftware EngineerTraverse an HTTP Maze with Retry Handling
This problem tests BFS traversal skills combined with state management for handling intermittent network failures and API constraints.
Coding & AlgorithmsOnsiteBFSGraphAPI - RedditMediumMachine Learning EngineerExclude Cat- or Dog-Related Comments and All Their Replies by Reader Mode
Given discussion comments that form reply trees, each flagged as being about cats, dogs, both or neither, return every comment a cat person or a dog person should not see, where hiding a comment also hides all of its replies. Tests reasoning over tree structure, edge cases such as missing parents, and complexity analysis.
Coding & AlgorithmsOnsite - RedditMediumSoftware EngineerImplement a sliding-window rate limiter
This problem tests your ability to design a rate-limiting algorithm that calculates traffic volume within a sliding time window to prevent API abuse.
Coding & AlgorithmsOnsiteHash MapSliding WindowRate Limiting - RedditMediumSoftware EngineerMerge Message Context Windows
This problem tests your ability to merge overlapping intervals efficiently using sorting and greedy techniques, a foundational skill for data reconciliation tasks.
Coding & AlgorithmsOnsiteIntervalsSortingGreedy - RedditHardMachine Learning EngineerSolve palindrome and list tasks
This problem tests your ability to manipulate string prefixes to satisfy palindromic properties and your skill in performing in-place linked list reordering based on node index parity.
Coding & AlgorithmsOnsiteStringLinked ListTwo Pointers - RemitlyMediumSoftware EngineerDesign an Elevator System and Scheduler
This question evaluates a candidate's object-oriented design and algorithmic scheduling competencies, focusing on concurrency control, fault tolerance, queue management, tie-breaking rules, and time/space complexity analysis within an elevator control system.
Coding & AlgorithmsOnsite - RemitlyMediumSoftware EngineerSolve k-Nearest Places by Latitude/Longitude
This question evaluates geospatial algorithm and systems-design competencies, focusing on nearest-neighbor search, great-circle distance computation, spatial indexing, and runtime/memory trade-offs for scalable location queries.
Coding & AlgorithmsOnsite - RemitlyMediumSoftware EngineerValidate a Bijective Substitution Cipher
Determine whether two printable ASCII strings form a valid one-to-one and onto (bijective) character substitution mapping.
Coding & AlgorithmsOnsiteHash TableStringAlgorithms - RipplingMediumSoftware EngineerAggregate expenses by person, trip, and category
This question evaluates a candidate's ability to perform efficient data aggregation, use associative data structures (maps/dictionaries), and reason about time and space complexity when processing large collections of records.
Coding & AlgorithmsOnsite - RipplingMediumSoftware EngineerCompare Complete or Partial Hands
This question evaluates implementation of card-hand evaluation logic, combinatorial reasoning about incomplete information, and deterministic tie-breaking rules for comparing complete and partial poker-like hands.
Coding & AlgorithmsOnsite - RipplingMediumSoftware EngineerDesign a music player with favorites cap
This question evaluates a candidate's ability to design and implement in-memory data structures, stateful APIs, concurrency handling, deterministic policy enforcement for a fixed-capacity favorites feature, and reasoning about edge cases like removing the currently playing track or handling invalid IDs.
Coding & AlgorithmsOnsite
Pinterest
Ramp
Reddit
Remitly
Rippling