Graph Traversal using BFS/DFS

Problem

Write a Python function that visits every node reachable from a specified starting node in an undirected graph. The graph is provided as an adjacency list, and your implementation may use either breadth-first search (BFS) or depth-first search (DFS).

Return the visited nodes as a list. Do not call graph-traversal utilities from Python's standard library.

Use this function signature:

def traverse_graph(adj_list, start):
    pass

Test Cases

• Input:

  • Adjacency List: [[1, 2], [0, 3], [0, 4], [1], [2]]
  • Starting Node: 0
  • Output: [0, 1, 2, 3, 4]
  • This result lists the nodes reachable from node 0 in a valid traversal order.

• Input:

  • Adjacency List: [[1, 3], [0, 2], [1], [0]]
  • Starting Node: 0
  • Output: [0, 1, 3, 2]
  • This ordering reflects one possible DFS visitation sequence. The exact order shown here is not required; any consistent order produced by a valid BFS or DFS traversal is acceptable.

Example

Input:

{"adj_list": [[1, 2], [0, 3], [0, 4], [1], [2]], "start": 0}

Output:

[0, 1, 2, 3, 4]

adj_list = [[1, 2], [0, 3], [0, 4], [1], [2]]
start = 0

[0, 1, 2, 3, 4]

The traversal begins at node 0 and reaches all five nodes in the graph.