ZorixOS
51+ X questions

X interview questions and how to prepare

The questions candidates report from X interviews, sorted by how often they come up, with difficulty and topics, plus original practice written in X's interview style.

Practice X questions free All companies

ZorixOS tracks 51 community-reported X interview questions, drawn from an open-source dataset of real interview reports and sorted by how frequently each one comes up. Every question links to its source. Alongside them are 77 original ZorixOS practice questions written in X's known interview style (not claimed as asked at X), so you can rehearse the real format. Practice any of them out loud in a free AI mock interview tuned to X.

Updated July 2026

X interview questions candidates report

Community-reported from real X interviews (open-source dataset), most-asked first. Showing 51. Each links to its source.

  1. Flatten Nested List Iterator
    StackTreeDepth-First SearchDesign
    Medium100% asked
  2. Largest Plus Sign
    ArrayDynamic Programming
    Medium100% asked
  3. LRU Cache
    Hash TableLinked ListDesignDoubly-Linked List
    Medium100% asked
  4. Merge Intervals
    ArraySorting
    Medium100% asked
  5. Trapping Rain Water
    ArrayTwo PointersDynamic ProgrammingStack
    Hard100% asked
  6. Tweet Counts Per Frequency
    Hash TableStringBinary SearchDesign
    Medium100% asked
  7. Alien Dictionary
    ArrayStringDepth-First SearchBreadth-First Search
    Hard97% asked
  8. Best Meeting Point
    ArrayMathSortingMatrix
    Hard97% asked
  9. Binary Gap
    Bit Manipulation
    Easy97% asked
  10. Count Student Number in Departments
    Database
    Medium97% asked
  11. Count Sub Islands
    ArrayDepth-First SearchBreadth-First SearchUnion-Find
    Medium97% asked
  12. Customer Placing the Largest Number of Orders
    Database
    Easy97% asked
  13. Design Authentication Manager
    Hash TableLinked ListDesignDoubly-Linked List
    Medium97% asked
  14. Design Skiplist
    Linked ListDesign
    Hard97% asked
  15. Design Twitter
    Hash TableLinked ListDesignHeap (Priority Queue)
    Medium97% asked
  16. Finding the Users Active Minutes
    ArrayHash Table
    Medium97% asked
  17. Flatten 2D Vector
    ArrayTwo PointersDesignIterator
    Medium97% asked
  18. Happy Number
    Hash TableMathTwo Pointers
    Easy97% asked
  19. Implement Trie (Prefix Tree)
    Hash TableStringDesignTrie
    Medium97% asked
  20. Insert Delete GetRandom O(1)
    ArrayHash TableMathDesign
    Medium97% asked
  21. Integer to Roman
    Hash TableMathString
    Medium97% asked
  22. Invalid Tweets
    Database
    Easy97% asked
  23. Investments in 2016
    Database
    Medium97% asked
  24. Kth Smallest Element in a Sorted Matrix
    ArrayBinary SearchSortingHeap (Priority Queue)
    Medium97% asked
  25. Lowest Common Ancestor of a Binary Search Tree
    TreeDepth-First SearchBinary Search TreeBinary Tree
    Medium97% asked
  26. Masking Personal Information
    String
    Medium97% asked
  27. Max Points on a Line
    ArrayHash TableMathGeometry
    Hard97% asked
  28. Merge k Sorted Lists
    Linked ListDivide and ConquerHeap (Priority Queue)Merge Sort
    Hard97% asked
  29. Minimum Elements to Add to Form a Given Sum
    ArrayGreedy
    Medium97% asked
  30. Minimum Genetic Mutation
    Hash TableStringBreadth-First Search
    Medium97% asked
  31. Minimum Number of Steps to Make Two Strings Anagram
    Hash TableStringCounting
    Medium97% asked
  32. Multiply Strings
    MathStringSimulation
    Medium97% asked
  33. Number of Black Blocks
    ArrayHash TableEnumeration
    Medium97% asked
  34. Number of Connected Components in an Undirected Graph
    Depth-First SearchBreadth-First SearchUnion-FindGraph Theory
    Medium97% asked
  35. One Edit Distance
    Two PointersString
    Medium97% asked
  36. Pascal's Triangle
    ArrayDynamic Programming
    Easy97% asked
  37. Permutation Sequence
    MathRecursion
    Hard97% asked
  38. Process Tasks Using Servers
    ArrayHeap (Priority Queue)
    Medium97% asked
  39. Rectangles Area
    Database
    Medium97% asked
  40. Regular Expression Matching
    StringDynamic ProgrammingRecursion
    Hard97% asked
  41. Remove All Occurrences of a Substring
    StringStackSimulation
    Medium97% asked
  42. Reverse Linked List
    Linked ListRecursion
    Easy97% asked
  43. The Skyline Problem
    ArrayDivide and ConquerBinary Indexed TreeSegment Tree
    Hard97% asked
  44. Time Needed to Buy Tickets
    ArrayQueueSimulation
    Easy97% asked
  45. Trapping Rain Water II
    ArrayBreadth-First SearchHeap (Priority Queue)Matrix
    Hard97% asked
  46. Tree Node
    Database
    Medium97% asked
  47. Valid Parentheses
    StringStack
    Easy97% asked
  48. Validate IP Address
    String
    Medium97% asked
  49. Wildcard Matching
    StringDynamic ProgrammingGreedyRecursion
    Hard97% asked
  50. Word Break II
    ArrayHash TableStringDynamic Programming
    Hard97% asked
  51. Minimum Cost to Connect Sticks
    ArrayGreedyHeap (Priority Queue)
    Medium86% asked

Practice questions in X's style

Original ZorixOS questions written the way X interviews, so you rehearse the real format. Not claimed as asked at X.

  1. Imagine X is experiencing a sudden surge in user-generated video uploads, causing latency spikes. How would you architect a system to handle this increased load while maintaining low upload times and ensuring video availability?

    Software EngineerSystem DesignTests: Evaluates the candidate's ability to design scalable and resilient systems for handling high throughput and real-time data processing, considering factors like caching, load balancing, and distributed storage.

  2. A popular feature on X, 'Live Spaces', is experiencing intermittent connection drops for a small but vocal percentage of users. Describe your debugging process, from initial report to identifying the root cause and proposing a solution. What tools and metrics would you leverage?

    Software EngineerDebuggingTests: Assesses the candidate's systematic approach to debugging complex, distributed systems and their familiarity with relevant diagnostic tools and techniques.

  3. Given X's vast user base, how would you design a rate limiter for the 'Direct Message' feature to prevent abuse while ensuring legitimate users have a smooth experience?

    Software EngineerSystem DesignTests: Tests the candidate's understanding of distributed system constraints, specifically concerning API abuse prevention and user experience trade-offs.

  4. Describe how you would implement a real-time notification system for new 'Trending Topics' on X, considering factors like fan-out, latency, and resource consumption.

    Software EngineerSystem DesignTests: Evaluates the candidate's knowledge of distributed messaging systems, event-driven architectures, and optimizing for low-latency, high-volume data dissemination.

  5. How would you approach designing a system to detect and mitigate coordinated inauthentic behavior on X, specifically focusing on the spread of misinformation or spam within 'Communities'?

    Software EngineerSystem DesignTests: Assesses the candidate's ability to design complex systems that address security and trust & safety challenges at scale, incorporating aspects of anomaly detection and mitigation.

  6. You're tasked with building a feature that allows users to create and share short-form video clips. Outline the core components of this system, from client-side recording to server-side processing and playback. What are the key technical challenges?

    Software EngineerSystem DesignTests: Measures the candidate's ability to break down a complex product feature into manageable technical components and identify potential bottlenecks.

71+ more X-style questions are in the free library, each practiceable live with adaptive follow-ups and an honest scorecard. Start free.

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X Interview Questions (2026) | ZorixOS