Count shortest distance in grid
Last updated: November 12, 2025
Quick Overview
Given a grid represented as a 2D matrix where each cell contains a non-negative integer representing the cost to enter that cell, write a function to calculate the shortest distance from the top-left corner to the bottom-right corner of the grid. The function should return the minimum cost to traverse from the starting point to the destination, moving only right or down. If the grid is empty, return 0.
Shopify
November 12, 202537
4
3,524 solved
Given a grid represented as a 2D matrix where each cell contains a non-negative integer representing the cost to enter that cell, write a function to calculate the shortest distance from the top-left corner to the bottom-right corner of the grid. The function should return the minimum cost to traverse from the starting point to the destination, moving only right or down. If the grid is empty, return 0.
Coding interviews at Shopify 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
- How would you test this solution thoroughly?
- How would your solution change if the input was sorted?
- How would you parallelize this solution?
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Problem Analysis
The problem can be analyzed using a Dynamic Programming approach. The primary goal is to find the minimum cost to reach the bottom-right corner of the grid, starting from the top-left corner. Give...
Approach
- Initialization: Start by checking if the grid is empty. If it is, return 0. Create a 2D list
dpof the same dimensions as the grid to store the minimum cost to reach each cell. - **Base Case...
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