Graph Traversal with BFS and DFS

At Notion, graph traversal is used to explore dependency graphs and connected components. Given a graph as an adjacency list and a starting node, implement both Breadth-First Search (BFS) and Depth-First Search (DFS) and return the order in which nodes are visited.

Formal Specification

Write a function graph_traversals(graph, start) where:

• graph is a dictionary mapping each node to a list of its neighbors
• start is the node where traversal begins
• Return a dictionary with two keys:
  • "bfs": list of nodes visited in BFS order
  • "dfs": list of nodes visited in DFS preorder

If start is not in the graph, return { "bfs": [], "dfs": [] }.

Traverse neighbors in the order they appear in the adjacency list.