Breadth-First Search Implementation

Unity tooling can model scene, prefab, and asset dependencies as a directed graph. Given an adjacency-list representation and a starting asset, return the nodes visited by a breadth-first search, preserving the neighbor order provided in the input.

Formal Specification

Implement bfs_graph(graph, start).

• graph is a dictionary where each key is a node identifier and its value is a list of directly reachable node identifiers.
• start is a node identifier. It may be omitted from graph, in which case it has no outgoing edges.
• Return a list containing every node reachable from start, in BFS order.
• Each node must appear at most once, even when the graph contains cycles or multiple paths to the same node.