BFS

from collections import deque

 

# BFS

def bfs(graph, start, visited):

    queue = deque([start])

    visited[start] = True

    while queue:

        v = queue.popleft()

        print(v, end=' ')

        for i in graph[v]:

            if visited[i] == False:

                visited[i] = True

                queue.append(i)

 

graph = [

    [],

    [2, 3, 8],

    [1, 7],

    [1, 4, 5],

    [3, 5],

    [3, 4],

    [7],

    [2, 6, 8],

    [1, 7],

]

visited = [False] * 9

bfs(graph, 1, visited)