Validate grid balanced
Last updated: August 31, 2025
Quick Overview
Determine if a given grid satisfies the valid BST property.
Coinbase
August 31, 202517
12
1,220 solved
Determine if a given grid satisfies the valid BST property.
This coding problem is frequently asked during Technical Screen at Coinbase. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. Coinbase 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
- How would your solution change if the input was sorted?
- What happens if the input contains duplicates?
- How would you modify your solution to handle streaming input?
- How would you test this solution thoroughly?
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