Find minimum cost in graph
Last updated: March 31, 2026
Quick Overview
Given a weighted, directed graph represented as an adjacency list, write a function to find the minimum cost to travel from a starting node to a target node. The function should take the graph, the starting node, and the target node as inputs and return the minimum cost as an integer. If the target node is unreachable, return -1.
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March 31, 2026125
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1,737 solved
Given a weighted, directed graph represented as an adjacency list, write a function to find the minimum cost to travel from a starting node to a target node. The function should take the graph, the starting node, and the target node as inputs and return the minimum cost as an integer. If the target node is unreachable, return -1.
Zoom uses this problem in the Take-home Project 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
- 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
- Can you solve this in a single pass?
- What happens if the input contains duplicates?
- Can you optimize the space complexity of your solution?
- How would you parallelize this solution?
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Practice DSA ProblemsSample Answer
Problem Analysis
The problem requires us to find the minimum cost to travel from a starting node to a target node in a weighted directed graph represented as an adjacency list. This is a classic shortest path problem,...
Approach
- Initialize a priority queue (min-heap) and a distance dictionary to store the minimum cost to reach each node, starting at the source node with a cost of 0.
- Insert the starting node and its cos...
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