Interview Cache
Master your next technical interview with real questions from industry leaders.
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213 problems across 4 categories
| Done | Title | Difficulty | Updated |
|---|---|---|---|
| Solve Tree Columns And Maze Variants Software EngineerCoding | Medium | May 21, 2026 | |
| Design Search And Web Crawling Systems Software EngineerSystem Design | Medium | May 21, 2026 | |
| Solve a Key-Door Corridor Maze Software EngineerCoding | Medium | May 14, 2026 | |
| Design an Instagram-Style Social Feed Software EngineerSystem Design | Medium | May 14, 2026 | |
| Measure scheduled posts feature success Data ScientistProduct Sense | Medium | Apr 30, 2026 | |
| Estimate ads ranking revenue impact Data ScientistProduct Sense | Medium | Apr 30, 2026 | |
| Compute ad impression conversion rates Data Scientist | Medium | Apr 30, 2026 | |
| Solve Array Merge and Parentheses Cleanup Software EngineerCoding | Medium | Apr 29, 2026 | |
| Solve Two Backtracking Array Problems Software EngineerCoding | Hard | Apr 27, 2026 | |
| Design an Online Game Leaderboard Software EngineerSystem Design | Hard | Apr 27, 2026 | |
| Design an Automated Ticket Investigation Agent Software EngineerSystem Design | Hard | Apr 27, 2026 | |
| Solve Maze and Suffix Problems Software EngineerCoding | Medium | Apr 25, 2026 | |
| Design an On-Demand Delivery Platform Software EngineerSystem Design | Medium | Apr 25, 2026 | |
| Solve Tree View and Triplet Sum Software EngineerCoding | Easy | Apr 24, 2026 | |
| Solve Tree Diameter and Palindromic Counts Software EngineerCoding | Medium | Apr 24, 2026 | |
| Solve Array, Matrix, and Recommendation Problems Software EngineerCoding | Medium | Apr 17, 2026 | |
| Design an Instagram-like Media Feed Software EngineerSystem Design | Medium | Apr 17, 2026 | |
| Find a String Containing Another Machine Learning EngineerCoding | Medium | Apr 16, 2026 | |
| Solve Subarray Sum and Local Minimum Software EngineerCoding | Hard | Apr 15, 2026 | |
| Validate abbreviations and brackets Site Reliability EngineerCoding | Medium | Apr 12, 2026 | |
| Troubleshoot a production server outage Site Reliability EngineerCoding | Medium | Apr 12, 2026 | |
| Solve Two String Problems Machine Learning EngineerCoding | Medium | Apr 12, 2026 | |
| Solve Parser, Trading, Tree, And Deck Tasks Software EngineerCoding | Medium | Apr 9, 2026 | |
| Prevent Private Code Leakage in Coding Agents Machine Learning EngineerSystem Design | Medium | Apr 9, 2026 | |
| Design Queue And Taxi Matching Services Software EngineerSystem Design | Medium | Apr 9, 2026 | |
| Solve coding and AI-assisted tasks Backend EngineerCoding | Medium | Apr 8, 2026 | |
| Infer an Unknown Alphabet Order Software EngineerCoding | Medium | Apr 8, 2026 | |
| Implement a Timestamped Banking System Software EngineerCoding | Hard | Apr 8, 2026 | |
| Design an Online Judge and Live Comments Software EngineerSystem Design | Medium | Apr 8, 2026 | |
| Design an Instagram-like platform Backend EngineerSystem Design | Medium | Apr 8, 2026 | |
| Troubleshoot a Midnight Web Server Outage Site Reliability EngineerCoding | Medium | Apr 6, 2026 | |
| Implement a Streaming VMStat Alert Site Reliability EngineerCoding | Medium | Apr 6, 2026 | |
| Solve delimiter and CSV tasks Software EngineerCoding | Medium | Apr 5, 2026 | |
| How should you evaluate unconnected content? Data ScientistProduct Sense | Medium | Apr 5, 2026 | |
| Count unconnected posts and reactions Data Scientist | Medium | Apr 5, 2026 | |
| Implement Multi-Level In-Memory Services Software EngineerCoding | Easy | Apr 4, 2026 | |
| Implement fast power and k-palindrome Software EngineerCoding | Medium | Apr 1, 2026 | |
| Implement an Expiring Record Store Software EngineerCoding | Medium | Apr 1, 2026 | |
| Should WhatsApp launch group calls? Data ScientistProduct Sense | Medium | Mar 24, 2026 | |
| Implement array parity and tree level views Software EngineerCoding | Easy | Mar 24, 2026 | |
| Count heavy callers in 7 days Data Scientist | Medium | Mar 24, 2026 | |
| Write SQL for call metrics Product AnalystProduct Sense | Medium | Mar 19, 2026 | |
| Solve Four Online Assessment Problems Software EngineerCoding | Medium | Mar 19, 2026 | |
| How would you grow Meta products? Product AnalystProduct Sense | Medium | Mar 19, 2026 | |
| Maximize Unique Characters from Words Software EngineerCoding | Medium | Mar 17, 2026 | |
| Design Place Recommendation System Machine Learning EngineerSystem Design | Medium | Mar 17, 2026 | |
| Design a Coding Contest Platform Software EngineerSystem Design | Medium | Mar 17, 2026 | |
| Design a Code Review Agent Software EngineerSystem Design | Medium | Mar 17, 2026 | |
| Write SQL for multi-account metrics Data Scientist | Medium | Mar 16, 2026 | |
| How to test account ranking change Data ScientistProduct Sense | Medium | Mar 16, 2026 | |
| Should WhatsApp Launch Group Calls? Data ScientistProduct Sense | Medium | Mar 14, 2026 | |
| Count Recent High-Volume Call Users Data Scientist | Medium | Mar 14, 2026 | |
| Assess Demand for Group Video Chat Data ScientistProduct Sense | Medium | Mar 14, 2026 | |
| Write SQL for CTR and Revenue Data Scientist | Medium | Mar 12, 2026 | |
| Solve array, tree, and maze problems Software EngineerCoding | Medium | Mar 12, 2026 | |
| Investigate Falling Brand-Ad Spend Data ScientistProduct Sense | Medium | Mar 12, 2026 | |
| Design a fitness tracking app Software EngineerSystem Design | Medium | Mar 12, 2026 | |
| Design marketplace experiments at DoorDash Data ScientistProduct Sense | Medium | Mar 11, 2026 | |
| Design an online auction system Software EngineerSystem Design | Easy | Mar 11, 2026 | |
| Design a location-based radius top-K search Software EngineerSystem Design | Easy | Mar 11, 2026 | |
| Implement an in-memory database with record locking Software EngineerCoding | Easy | Mar 8, 2026 | |
| Write SQL for reply-based recipient metrics Data Scientist | Hard | Mar 5, 2026 | |
| How would you evaluate stolen-post detection? Data ScientistProduct Sense | Hard | Mar 5, 2026 | |
| Should We Launch Group Calling? Data ScientistProduct Sense | Hard | Mar 4, 2026 | |
| Design a marketplace price tracking service Software EngineerSystem Design | Medium | Mar 4, 2026 | |
| Construct a BST and read spiral order Software EngineerCoding | Medium | Mar 4, 2026 | |
| Compute High-Call Usage Rates Data Scientist | Hard | Mar 4, 2026 | |
| Write SQL for seller and vehicle metrics Data Scientist | Medium | Mar 2, 2026 | |
| How to evaluate new listing notifications? Data ScientistProduct Sense | Medium | Mar 2, 2026 | |
| Write queries for follows and bookings Data EngineerCoding | Medium | Mar 1, 2026 | |
| Optimize a Fifteen-Sum Card Strategy Machine Learning EngineerCoding | Hard | Mar 1, 2026 | |
| Find Words Containing Other Words Machine Learning EngineerCoding | Hard | Mar 1, 2026 | |
| Find Maximum Unique-Character Subset Machine Learning EngineerCoding | Hard | Mar 1, 2026 | |
| Extend a Maze Solver Machine Learning EngineerCoding | Hard | Mar 1, 2026 | |
| Evaluate AI-assisted ad creation Data ScientistProduct Sense | Medium | Mar 1, 2026 | |
| Define metrics and data model for product features Data EngineerSystem Design | Medium | Mar 1, 2026 | |
| Build a Friend Recommender Machine Learning EngineerCoding | Hard | Mar 1, 2026 | |
| Assess Group Video Chat Demand Data ScientistProduct Sense | Medium | Mar 1, 2026 | |
| Analyze spend and creation-source shifts Data Scientist | Medium | Mar 1, 2026 | |
| Solve Merge Lists and Vertical Traversal Machine Learning EngineerCoding | Medium | Feb 28, 2026 | |
| Design a Short-Video Recommendation System Machine Learning EngineerSystem Design | Medium | Feb 28, 2026 | |
| Check and infer custom alphabet Software EngineerCoding | Hard | Feb 28, 2026 | |
| Solve Tree Views, Columns, and Calculator Machine Learning EngineerCoding | Easy | Feb 27, 2026 | |
| Design an Online Coding Judge Machine Learning EngineerSystem Design | Easy | Feb 27, 2026 | |
| Find top-K frequent elements in a stream Software EngineerCoding | Medium | Feb 25, 2026 | |
| Design real-time live comments Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Design an online coding judge Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Design an online chess platform Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Design an online auction system Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Design an Instagram-style news feed Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Design an ad click aggregation service Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Design a YouTube/Netflix video platform Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Design a ticket or hotel reservation system Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Design a ride-sharing system like Uber Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Design a real-time game leaderboard Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Design a price drop tracking service Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Design a post privacy/visibility system Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Design a nearby places (proximity) service Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Design a large-scale web crawler Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Design a Dropbox/Google Drive sync service Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Design a distributed job scheduler Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Design a chat messaging system Software EngineerSystem Design | Medium | Feb 25, 2026 | |
| Evaluate AI-assisted ad creation Data ScientistProduct Sense | Medium | Feb 23, 2026 | |
| Analyze spend cohort and source shifts Data Scientist | Medium | Feb 23, 2026 | |
| Design experiments and diagnose metric changes Product AnalystProduct Sense | Easy | Feb 22, 2026 | |
| Measure fake account prevalence Data ScientistProduct Sense | Medium | Feb 22, 2026 | |
| Find least active countries Data Scientist | Medium | Feb 22, 2026 | |
| Find Kth Largest and Tree Ancestors Software EngineerCoding | Medium | Feb 22, 2026 | |
| Evaluate an ads algorithm change Data ScientistProduct Sense | Medium | Feb 22, 2026 | |
| How would you evaluate emoji reactions launch? Data ScientistProduct Sense | Easy | Feb 21, 2026 | |
| Analyze DoorDash marketplace product decisions Product AnalystProduct Sense | Medium | Feb 19, 2026 | |
| How would you evaluate pixel-issue notifications? Data ScientistProduct Sense | Easy | Feb 18, 2026 | |
| How would you define and use retention metrics? Data ScientistProduct Sense | Easy | Feb 18, 2026 | |
| How to measure harmful-content severity and run experiments Data ScientistProduct Sense | Easy | Feb 18, 2026 | |
| Design a Trade Ledger Class Software EngineerCoding | Easy | Feb 18, 2026 | |
| Compute Range Sum Quickly Software EngineerCoding | Easy | Feb 18, 2026 | |
| Remove minimum invalid mixed brackets Software EngineerCoding | Hard | Feb 17, 2026 | |
| Connect next pointers for each tree level Software EngineerCoding | Hard | Feb 17, 2026 | |
| Investigate why an advertiser’s spend decreased Data ScientistProduct Sense | Easy | Feb 16, 2026 | |
| Detect bots using comment distribution patterns Data ScientistProduct Sense | Easy | Feb 16, 2026 | |
| Convert multi-currency revenue to USD totals Data Scientist | Easy | Feb 16, 2026 | |
| Compute CTR for peak vs non-peak hours Data Scientist | Easy | Feb 16, 2026 | |
| Compare performance of FB vs IG Stories Data ScientistProduct Sense | Easy | Feb 16, 2026 | |
| Detect fake accounts and measure their impact Analytics EngineerProduct Sense | Easy | Feb 15, 2026 | |
| Design and evaluate an ads ranking algorithm Analytics Engineer | Easy | Feb 15, 2026 | |
| Compute daily active ads Analytics Engineer | Easy | Feb 15, 2026 | |
| Evaluate AI-assisted ads creation feature Data ScientistProduct Sense | Easy | Feb 15, 2026 | |
| Compute this-year spend share of last-year whales Data Scientist | Easy | Feb 15, 2026 | |
| Analyze and mitigate fake advertiser accounts Data ScientistProduct Sense | Easy | Feb 15, 2026 | |
| Write SQL for seller and category metrics Data Scientist | Medium | Feb 15, 2026 | |
| Evaluate a new-listing notification feature Data ScientistProduct Sense | Medium | Feb 15, 2026 | |
| How would you evaluate upranking shop ads? Data ScientistProduct Sense | Easy | Feb 12, 2026 | |
| How would you design a Shop Ads ranking algorithm? Data Scientist | Easy | Feb 12, 2026 | |
| Solve frequency and tree-completeness problems Machine Learning EngineerCoding | Medium | Feb 12, 2026 | |
| Solve four OA string/array/matrix/graph tasks Machine Learning EngineerCoding | Easy | Feb 12, 2026 | |
| Maximize unique characters from a word list Machine Learning EngineerCoding | Medium | Feb 12, 2026 | |
| Implement weighted random sampling with preprocessing Machine Learning EngineerCoding | Medium | Feb 12, 2026 | |
| Extend BFS maze solver with keys and arrows Software EngineerCoding | Medium | Feb 12, 2026 | |
| Determine feasibility and clean parentheses string Software EngineerCoding | Medium | Feb 12, 2026 | |
| Design content moderation for a posting app Software EngineerSystem Design | Medium | Feb 12, 2026 | |
| Design an image copyright-violation detection system Machine Learning EngineerSystem Design | Medium | Feb 12, 2026 | |
| Design a recommendation system from scratch Machine Learning EngineerSystem Design | Medium | Feb 12, 2026 | |
| Debug and optimize a card-drawing strategy Machine Learning EngineerCoding | Medium | Feb 12, 2026 | |
| Compute the next lexicographic permutation Machine Learning EngineerCoding | Medium | Feb 12, 2026 | |
| Solve three array/string/graph coding tasks Software EngineerCoding | Medium | Feb 11, 2026 | |
| Solve maze tasks and compute shortest routes Software EngineerCoding | Medium | Feb 11, 2026 | |
| Maximize concatenation length with unique chars Machine Learning EngineerCoding | Medium | Feb 11, 2026 | |
| Implement an in-memory key-field-value DB with TTL Software EngineerCoding | Medium | Feb 11, 2026 | |
| Implement a versioned in-memory DB with CAS and history Software EngineerCoding | Medium | Feb 11, 2026 | |
| Extend cloud file system with copy and compression Software EngineerCoding | Medium | Feb 11, 2026 | |
| Extend a BFS maze solver stepwise Software EngineerCoding | Medium | Feb 11, 2026 | |
| Design an in-memory cloud file system Software EngineerCoding | Medium | Feb 11, 2026 | |
| Design a Top-K trending items service Software EngineerSystem Design | Medium | Feb 11, 2026 | |
| Design a system to detect weapon posts Machine Learning EngineerSystem Design | Medium | Feb 11, 2026 | |
| Design a live video comments system Software EngineerSystem Design | Medium | Feb 11, 2026 | |
| Design a bank system with scheduled transfers Software EngineerCoding | Medium | Feb 11, 2026 | |
| Compute sparse dot product and count islands Software EngineerCoding | Medium | Feb 11, 2026 | |
| Solve maze reachability and two follow-ups Software EngineerCoding | Medium | Feb 7, 2026 | |
| Design an online coding contest platform Software EngineerSystem Design | Medium | Feb 7, 2026 | |
| Evaluate account re-ranking via logs and A/B test Data ScientistProduct Sense | Easy | Feb 3, 2026 | |
| Compute multi-account user distribution and unread pct Data Scientist | Easy | Feb 3, 2026 | |
| Write SQL for call pickup and usage metrics Product AnalystProduct Sense | Easy | Feb 2, 2026 | |
| How would you grow key product metrics? Product AnalystProduct Sense | Easy | Feb 2, 2026 | |
| Troubleshoot a single-node web outage Software EngineerSystem Design | Medium | Jan 22, 2026 | |
| Solve string transform and min-move sorting Software EngineerCoding | Medium | Jan 22, 2026 | |
| Find two numbers summing to target without hashmap Machine Learning EngineerCoding | Medium | Jan 22, 2026 | |
| Design a weapon-ad harmful content detection system Machine Learning EngineerSystem Design | Medium | Jan 22, 2026 | |
| Deep copy a linked list with random pointers Machine Learning EngineerCoding | Medium | Jan 22, 2026 | |
| Implement LRU cache and copy random list Machine Learning EngineerCoding | Medium | Jan 21, 2026 | |
| Find shortest path in a maze grid Machine Learning EngineerCoding | Medium | Jan 21, 2026 | |
| Design an ads ranking system with calibration Machine Learning EngineerSystem Design | Medium | Jan 21, 2026 | |
| Maximize score in 15-sum card game Software EngineerCoding | Medium | Jan 18, 2026 | |
| Design coding platform with global leaderboard Software EngineerSystem Design | Medium | Jan 18, 2026 | |
| Compute unmatched parentheses length Software EngineerCoding | Medium | Jan 18, 2026 | |
| Compute dot product of sparse vectors Software EngineerCoding | Medium | Jan 18, 2026 | |
| How to evaluate similar-listing notifications feature Data ScientistProduct Sense | Easy | Jan 17, 2026 | |
| Evaluate new shop-ads ranking algorithm Data ScientistProduct Sense | Easy | Jan 17, 2026 | |
| Compute probability an account is fake Data Scientist | Easy | Jan 17, 2026 | |
| Compute ads revenue by geography in SQL Data Scientist | Easy | Jan 17, 2026 | |
| Implement cd and merge intervals Software EngineerCoding | Medium | Jan 16, 2026 | |
| Implement exponentiation and fill grid distances Machine Learning EngineerCoding | Medium | Jan 8, 2026 | |
| Validate parentheses and find k-th largest Software EngineerCoding | Medium | Jan 6, 2026 | |
| Design a ranking and recommendation system Software EngineerSystem Design | Medium | Jan 6, 2026 | |
| Count three-digit numbers with distinct digits Software EngineerCoding | Hard | Jan 6, 2026 | |
| Answer four array/time/grid query questions Software EngineerCoding | Medium | Jan 6, 2026 | |
| Troubleshoot a website outage with disk full Software EngineerCoding | Medium | Jan 5, 2026 | |
| Solve counting and frequency coding tasks Software EngineerCoding | Medium | Jan 5, 2026 | |
| Return right and left side views of a tree Software EngineerCoding | Medium | Jan 5, 2026 | |
| Implement solutions to several coding tasks Machine Learning EngineerCoding | Medium | Jan 5, 2026 | |
| Find shortest path in an OOP maze Software EngineerCoding | Medium | Jan 5, 2026 | |
| Design a weapon-sale ad detection system Machine Learning EngineerSystem Design | Medium | Jan 5, 2026 | |
| Design a food ordering and delivery system Software EngineerSystem Design | Medium | Jan 5, 2026 | |
| Add two binary strings Software EngineerCoding | Medium | Jan 5, 2026 | |
| Implement power, reduce string, parse tree, debug maze Software EngineerCoding | Medium | Jan 1, 2026 | |
| Design ad click tracking and dashboard at scale Software EngineerSystem Design | Medium | Jan 1, 2026 | |
| Design metrics and experiment for stolen-post detection Data ScientistProduct Sense | Easy | Dec 18, 2025 | |
| Compute reply-based user metrics in 7 days Data Scientist | Easy | Dec 18, 2025 | |
| Answer four string/array/battery coding questions Software EngineerCoding | Medium | Dec 16, 2025 | |
| Validate near-palindrome and course prerequisite feasibility Software EngineerCoding | Medium | Dec 15, 2025 | |
| Solve shipping capacity and expression insertion Machine Learning EngineerCoding | Medium | Dec 15, 2025 | |
| Solve linked list, tree, and grid problems Machine Learning EngineerCoding | Medium | Dec 15, 2025 | |
| Select words to maximize unique characters Software EngineerCoding | Medium | Dec 15, 2025 | |
| Return all root-to-leaf path sums Software EngineerCoding | Medium | Dec 15, 2025 | |
| Merge overlapping time intervals Software EngineerCoding | Easy | Dec 15, 2025 | |
| Implement weighted random city and sparse dot product Machine Learning EngineerCoding | Medium | Dec 15, 2025 | |
| Design weapon-selling ad detection from posts Machine Learning EngineerSystem Design | Medium | Dec 15, 2025 | |
| Design comment ranking for a news feed Machine Learning EngineerSystem Design | Medium | Dec 15, 2025 | |
| Design a Netflix-like video streaming service Software EngineerSystem Design | Medium | Dec 15, 2025 | |
| Convert 32-bit integer to hexadecimal Software EngineerCoding | Medium | Dec 15, 2025 | |
| Compute nested depth sum and grid distance Machine Learning EngineerCoding | Medium | Dec 15, 2025 | |
| Solve two linked list/array tasks Machine Learning EngineerCoding | Easy | Dec 14, 2025 | |
| Solve array merge, tree view, and maze tasks Machine Learning EngineerCoding | Medium | Dec 9, 2025 | |
| Design recommendation and weapon-ad detection systems Machine Learning EngineerSystem Design | Medium | Dec 9, 2025 |