Implement Skip List with with follow-up
Last updated: March 31, 2026
Quick Overview
Implement a Skip List data structure that supports search, insert, and delete operations with an average time complexity of O(log n). Your implementation should allow for efficient traversal and maintain a probabilistic balance of the list. The input will consist of a series of integers to be inserted or searched, and the output should indicate whether the search was successful or confirm the insertion or deletion of elements.
Square/Block
March 31, 2026252
11
3,596 solved
Implement a Skip List data structure that supports search, insert, and delete operations with an average time complexity of O(log n). Your implementation should allow for efficient traversal and maintain a probabilistic balance of the list. The input will consist of a series of integers to be inserted or searched, and the output should indicate whether the search was successful or confirm the insertion or deletion of elements.
Square/Block uses this problem in the Take-home Project to evaluate your algorithmic thinking. They expect you to discuss multiple approaches, analyze trade-offs between them, and implement the optimal solution with clean, readable code.
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
- How would your solution change if the input was sorted?
- Can you solve this iteratively instead of recursively (or vice versa)?
- How would you parallelize this solution?
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Practice DSA ProblemsSample Answer
Problem Analysis
The Skip List is a probabilistic data structure that allows for O(log n) average time complexity for search, insert, and delete operations. The underlying pattern here is a layered linked list where e...
Approach
- Data Structure Definition: Define a
Nodeclass with attributes for the value and a list of forward pointers. Define aSkipListclass that keeps track of the head node and maximum level. 2....
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