Count minimum cost in grid
Last updated: July 8, 2025
Quick Overview
Given a grid of non-negative integers representing the cost of moving through each cell, write a function to calculate the minimum cost to travel from the top-left corner to the bottom-right corner of the grid, moving only down or right. The function should take a 2D array as input and return an integer representing the minimum cost.
Zscaler
July 8, 2025191
8
1,127 solved
Given a grid of non-negative integers representing the cost of moving through each cell, write a function to calculate the minimum cost to travel from the top-left corner to the bottom-right corner of the grid, moving only down or right. The function should take a 2D array as input and return an integer representing the minimum cost.
This coding problem is frequently asked during Technical Screen at Zscaler. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. Zscaler 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?
- How would you modify your solution to handle streaming input?
- Can you solve this in a single pass?
- How would you test this solution thoroughly?
Sharpen Your Skills on Codemia
Practice similar problems with our interactive workspace, get AI feedback, and track your progress.
Practice DSA ProblemsSample Answer
Problem Analysis
This problem can be effectively solved using Dynamic Programming. The reason this technique applies here is that we can break down the problem into smaller subproblems: the minimum cost to reach a...
Approach
-
Initialization: Create a 2D array
dpof the same size as the input grid to store the minimum costs. Setdp[0][0]togrid[0][0]since that's the starting point. -
**Fill the First Row an...
Submit Your Answer
