Implement Hash Map with O(1) space
Last updated: March 29, 2026
Quick Overview
Implement a Deque data structure that supports push, pop, and peek operations in O(n) time.
HashiCorp
March 29, 202649
13
565 solved
Implement a Deque data structure that supports push, pop, and peek operations in O(n) time.
Coding interviews at HashiCorp 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
- Identify the correct data structure and algorithm for the problem
- Write clean, bug-free code with proper variable naming
- Analyze time and space complexity correctly
- Handle basic edge cases (empty input, single element)
- Communicate your thought process while coding
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 you modify your solution to handle streaming input?
- What if the input doesn't fit in memory?
- How would you parallelize this solution?
- How would you test this solution thoroughly?
Sharpen Your Skills on Codemia
Practice similar problems with our interactive workspace, get AI feedback, and track your progress.
Practice DSA ProblemsSample Answer
Problem Analysis
Start by understanding the input/output format and constraints. Identify the core problem pattern. Ask clarifying questions: Is the input sorted? Can ...
Brute Force Approach
Always start with the simplest correct solution, even if it's not optimal. This shows you can solve the problem and gives you a baseline to optimize f...
Submit Your Answer
HashiCorp Machine Learning Engineer Interview Guide
Interview process, tips, and preparation timeline