Count shortest distance in graph
Last updated: October 15, 2025
Quick Overview
Given an undirected graph represented as an adjacency list, write a function to calculate the shortest distance between two specified nodes. The function should take the graph, the starting node, and the target node as inputs, and return the shortest distance as an integer. If there is no path between the nodes, return -1.
Cockroach Labs
October 15, 20259
10
1,708 solved
Given an undirected graph represented as an adjacency list, write a function to calculate the shortest distance between two specified nodes. The function should take the graph, the starting node, and the target node as inputs, and return the shortest distance as an integer. If there is no path between the nodes, return -1.
Coding interviews at Cockroach Labs 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
- Identify the correct data structure and algorithm for the problem
- Write clean, bug-free code with proper variable naming
- Analyze time and space complexity correctly
- Handle basic edge cases (empty input, single element)
- Communicate your thought process while coding
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 optimize the space complexity of your solution?
- Can you solve this in a single pass?
- How would you test this solution thoroughly?
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Practice DSA ProblemsSample Answer
Problem Analysis
To solve the problem of finding the shortest distance between two nodes in an undirected graph represented as an adjacency list, we can utilize the Breadth-First Search (BFS) algorithm. BFS is par...
Approach
- Initialize a queue: Start by creating a queue to facilitate BFS. Add the starting node to the queue along with its distance from itself (0).
- Set up a visited set: This will help us keep...
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