Implement Stack with O(n) time
Last updated: February 9, 2026
Quick Overview
Implement a stack data structure that supports push, pop, and top operations, ensuring that each operation runs in O(n) time. The stack should be able to handle integer values, and you should provide methods to retrieve the top element without removing it. Additionally, ensure that the stack can be cleared, resetting its state.
Anduril
February 9, 20264
3
351 solved
Implement a stack data structure that supports push, pop, and top operations, ensuring that each operation runs in O(n) time. The stack should be able to handle integer values, and you should provide methods to retrieve the top element without removing it. Additionally, ensure that the stack can be cleared, resetting its state.
Coding interviews at Anduril 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
- Can you optimize the space complexity of your solution?
- How would your solution change if the input was sorted?
- How would you parallelize this solution?
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
To implement a stack with O(n) time complexity for each operation (push, pop, and top), we can utilize a list to store the elements. The reason O(n) applies here is that we will rearrange the elements...
Approach
- Data Structure: Use a Python list to hold the stack elements.
- Push Operation: When pushing an element, we will add it to the end of the list. To ensure O(n) time, we will traverse throug...
Submit Your Answer
