Validate grid sorted
Last updated: August 31, 2025
Quick Overview
Given a 2D grid of integers, write a function to determine if the grid is sorted in non-decreasing order both row-wise and column-wise. The function should return true if the grid satisfies this condition, and false otherwise. The input will be a 2D list of integers, and the output will be a boolean value.
CrowdStrike
August 31, 202529
7
1,384 solved
Given a 2D grid of integers, write a function to determine if the grid is sorted in non-decreasing order both row-wise and column-wise. The function should return true if the grid satisfies this condition, and false otherwise. The input will be a 2D list of integers, and the output will be a boolean value.
CrowdStrike 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
- Quickly identify the optimal approach and its theoretical basis
- Handle complex algorithm design with multiple interacting components
- Write concise, elegant code under time pressure
- Prove correctness of your approach and discuss alternative solutions
- Optimize beyond the obvious: discuss constant factor improvements
- Address follow-up variations and explain how the solution generalizes
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 you test this solution thoroughly?
- How would you parallelize this solution?
- What if the input doesn't fit in memory?
- Can you optimize the space complexity of your solution?
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Practice DSA ProblemsSample Answer
Problem Analysis
To determine if the 2D grid is sorted in non-decreasing order both row-wise and column-wise, we can utilize a straightforward approach without needing complex data structures. The problem fundamentall...
Approach
- Iterate through each row of the grid. For each row, check if each element is less than or equal to the next element. If any pair of elements violates this condition, return false.
- After confirmi...
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