Implement Hash Map with streaming input
Last updated: April 28, 2026
Quick Overview
Design and implement a hash map that can handle streaming input, allowing for efficient insertion and retrieval of key-value pairs. The hash map should support operations such as `put(key, value)` to add or update entries and `get(key)` to retrieve values in average O(1) time complexity. Ensure that the implementation can handle collisions appropriately and can manage a dynamic set of inputs.
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Design and implement a hash map that can handle streaming input, allowing for efficient insertion and retrieval of key-value pairs. The hash map should support operations such as `put(key, value)` to add or update entries and `get(key)` to retrieve values in average O(1) time complexity. Ensure that the implementation can handle collisions appropriately and can manage a dynamic set of inputs.
Coding interviews at Pinterest 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
- What if the input doesn't fit in memory?
- How would you parallelize this solution?
- Can you optimize the space complexity of your solution?
- What happens if the input contains duplicates?
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Practice DSA ProblemsSample Answer
Problem Analysis
The problem requires us to design a hash map that can handle streaming input, meaning it must dynamically accommodate new entries while maintaining efficient retrieval. The specific pattern that appli...
Approach
To implement the hash map, we will follow these steps:
- Initialize the Hash Map: Create an array of a fixed size to hold the entries. Each entry will be a linked list to handle collisions.
- **...
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