Count maximum path in string
Last updated: October 28, 2025
Quick Overview
Count the number of cycle in the given binary tree.
ServiceNow
October 28, 202510
13
3,278 solved
Count the number of cycle in the given binary tree.
ServiceNow uses this problem in the Technical Screen to evaluate your algorithmic thinking. They expect you to discuss multiple approaches, analyze trade-offs between them, and implement the optimal solution with clean, readable code.
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 solve this iteratively instead of recursively (or vice versa)?
- How would you parallelize this solution?
- What if the input doesn't fit in memory?
- How would you modify your solution to handle streaming input?
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Practice DSA ProblemsSample Answer
Problem Analysis
The key issue in this exact question is that a true binary tree cannot contain cycles by definition. If a structure has a cycle, it is no longer a val...
Approach
Use DFS with three states for each node: - `0` or missing: node has not been visited - `1`: node is currently in the recursion path - `2`: node and a...
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