This question evaluates understanding of graph traversal and shortest-path concepts, specifically the differences between BFS and DFS, algorithmic complexity analysis, and adaptation for weighted graphs within the coding & algorithms domain.

Given an unweighted graph (directed or undirected), explain how to find the shortest path between two nodes without writing code. Describe the algorithm step by step, analyze time and space complexity, and justify why it works. Compare this approach using BFS with a DFS-based approach: when would each be appropriate, and what are the trade-offs in correctness, complexity, and memory? Briefly discuss how your approach changes for weighted graphs.