Detect palindrome in linked list
Last updated: May 20, 2026
Quick Overview
Given a singly linked list, determine if the sequence of values in the list forms a palindrome. A palindrome reads the same forwards and backwards. The function should return a boolean value: true if the linked list is a palindrome, and false otherwise.
CrowdStrike
May 20, 2026140
15
2,797 solved
Given a singly linked list, determine if the sequence of values in the list forms a palindrome. A palindrome reads the same forwards and backwards. The function should return a boolean value: true if the linked list is a palindrome, and false otherwise.
This coding problem is frequently asked during Phone Screen at CrowdStrike. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. CrowdStrike expects candidates to write production-quality code, not just solve the puzzle.
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 is the worst-case input for your solution?
- Can you solve this in a single pass?
- Can you optimize the space complexity of your solution?
- Can you solve this iteratively instead of recursively (or vice versa)?
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Problem Analysis
To determine if a singly linked list is a palindrome, we can utilize the two-pointer technique. This approach is suitable here because it allows us to traverse the linked list efficiently and comp...
Approach
- Find the Midpoint: Use two pointers; one (slow) moves one step at a time, and the other (fast) moves two steps. When the fast pointer reaches the end, the slow pointer will be at the midpoint. ...
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