Implement Skip List with streaming input

Last updated: December 14, 2025

Quick Overview

Implement a Priority Queue data structure that supports insert, delete, and lookup operations in O(n) time.

Jane Street
Coding & Algorithms
Software Engineer
Jane Street
December 14, 2025
Software Engineer
Onsite
Coding & Algorithms
Medium

133

9

3,411 solved


Implement a Priority Queue data structure that supports insert, delete, and lookup operations in O(n) time.

This coding problem is frequently asked during Onsite at Jane Street. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. Jane Street expects candidates to write production-quality code, not just solve the puzzle.

What the Interviewer Expects
  • Recognize the underlying problem pattern (sliding window, two pointers, BFS/DFS, etc.)
  • Discuss multiple approaches and trade-offs before coding
  • Implement an optimal solution with clean, production-quality code
  • Handle all edge cases including boundary conditions and invalid input
  • Optimize both time and space complexity with clear justification
  • Test your solution systematically with well-chosen examples
Key Topics to Cover
Data structure selection and trade-offs
Common algorithm patterns (sliding window, two pointers, BFS/DFS)
Sorting and searching
Time and space complexity analysis
Edge cases and input validation
How to Approach This
  1. Clarify input constraints and edge cases before writing code.
  2. Walk through your approach verbally and confirm with the interviewer before coding.
  3. Start with a brute force solution, then optimize. Mention time and space complexity.
  4. Test your solution with examples, including edge cases like empty input or duplicates.
  5. Consider common patterns: sliding window, two pointers, hash map, BFS/DFS, dynamic programming.
Possible Follow-up Questions
  • Can you optimize the space complexity of your solution?
  • How would your solution change if the input was sorted?
  • How would you test this solution thoroughly?
  • Can you solve this iteratively instead of recursively (or vice versa)?
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Sample Answer
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