How do I implement Breadth-First Search (BFS) in Python?

Can you explain how to implement Breadth-First Search in Python?

Sure! Breadth-First Search (BFS) is an algorithm for traversing or searching tree or graph data structures. It explores all the neighbor nodes at the present depth prior to moving on to nodes at the next depth level.

What data structures do I need for BFS?

You'll need a queue to keep track of the nodes to be explored and a set to keep track of visited nodes.

Can you provide a sample code for BFS?

Absolutely! Here's a simple implementation in Python:

from collections import deque

def bfs(graph, start):
    visited = set()
    queue = deque([start])

    while queue:
        vertex = queue.popleft()
        if vertex not in visited:
            print(vertex)
            visited.add(vertex)
            queue.extend(neighbor for neighbor in graph[vertex] if neighbor not in visited)

How do I represent a graph in Python?

You can represent a graph using a dictionary where keys are node values and values are lists of adjacent nodes. For example:

graph = { 
    'A': ['B', 'C'],
    'B': ['A', 'D', 'E'],
    'C': ['A', 'F'],
    'D': ['B'],
    'E': ['B', 'F'],
    'F': ['C', 'E']
}