Implement Hash Map with without recursion
Last updated: January 16, 2026
Quick Overview
Implement a hash map data structure that supports basic operations such as insert, delete, and get without using recursion. Your implementation should handle collisions using chaining or open addressing and should provide average time complexity of O(1) for these operations. The input will consist of key-value pairs for insertion and keys for retrieval and deletion, with the output being the value associated with a key or a confirmation of deletion.
Jane Street
January 16, 202610
14
1,422 solved
Implement a hash map data structure that supports basic operations such as insert, delete, and get without using recursion. Your implementation should handle collisions using chaining or open addressing and should provide average time complexity of O(1) for these operations. The input will consist of key-value pairs for insertion and keys for retrieval and deletion, with the output being the value associated with a key or a confirmation of deletion.
Coding interviews at Jane Street focus on problem-solving approach as much as the final solution. The interviewer wants to see you break down the problem, consider edge cases, and optimize iteratively. Communication throughout the process is key.
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 you parallelize this solution?
- Can you solve this iteratively instead of recursively (or vice versa)?
- What if the input doesn't fit in memory?
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Practice DSA ProblemsSample Answer
Problem Analysis
This problem involves creating a hash map, which is a data structure that allows for efficient key-value pair storage and retrieval. Given the requirement for operations like insert, delete, and get t...
Approach
- Hash Function: Define a simple hash function that maps keys to an index in the hash table. For instance, we can use Python's built-in
hash()function, followed by modulus operation with the s...
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