Implement Skip List with streaming input
Last updated: December 14, 2025
Quick Overview
Implement a Skip List data structure that supports insertion, deletion, and search operations with logarithmic expected time complexity. The Skip List should be able to handle streaming input, allowing for dynamic updates as new elements are added. Your implementation should include methods for inserting elements, removing elements, and searching for elements, along with appropriate handling of edge cases.
Jane Street
December 14, 2025133
9
3,411 solved
Implement a Skip List data structure that supports insertion, deletion, and search operations with logarithmic expected time complexity. The Skip List should be able to handle streaming input, allowing for dynamic updates as new elements are added. Your implementation should include methods for inserting elements, removing elements, and searching for elements, along with appropriate handling of edge cases.
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
How to Approach This
- Clarify input constraints and edge cases before writing code.
- Walk through your approach verbally and confirm with the interviewer before coding.
- Start with a brute force solution, then optimize. Mention time and space complexity.
- Test your solution with examples, including edge cases like empty input or duplicates.
- 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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Practice DSA ProblemsSample Answer
Problem Analysis
The problem requires implementing a Skip List, which is a probabilistic data structure that allows for fast search, insertion, and deletion operations. The underlying pattern here is a layered linked ...
Approach
- Structure Definition: Define a
Nodeclass with attributes for value and pointers to the next nodes at different levels. Define aSkipListclass that maintains the head of the list and the m...
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