Detect permutation in string
Last updated: May 25, 2026
Quick Overview
Given two strings, determine if one string is a permutation of the other. The function should take two input strings and return a boolean indicating whether they contain the same characters in a different order, ignoring spaces and case sensitivity.
PayPal
May 25, 202638
3
4,114 solved
Given two strings, determine if one string is a permutation of the other. The function should take two input strings and return a boolean indicating whether they contain the same characters in a different order, ignoring spaces and case sensitivity.
Coding interviews at PayPal 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 solve this iteratively instead of recursively (or vice versa)?
- How would you parallelize this solution?
- How would your solution change if the input was sorted?
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 determine if one string is a permutation of another, we need to check if both strings contain the exact same characters with the same frequency, while ignoring spaces and case sensitivity. This pro...
Approach
- Normalize the Input: Convert both strings to lowercase and remove any spaces.
- Check Lengths: If the lengths of the two normalized strings are different, immediately return
False. - **...
Submit Your Answer
