n = len(graph.adjList) # to keep track of whether a vertex is discovered or not discovered = [False] * n # create a queue for doing BFS q = deque() # mark the source vertex as discovered discovered[src] = True # enqueue source vertex q.append(src)

The function bfs will perform the BFS algorithm for a graph using adjacency list representation. We will look at the code for the bfs function and explain it line by line.