BFS

example_bfs.py

#!/usr/env/python

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

visited = []
queue = []

def bfs(visited, graph, node):
   visited.append(node)
   queue.append(node)
   while queue:
      s = queue.pop(0)
      print(s, end=" ")
      for neighbour in graph[s]:
          if neighbour not in visited:
              visited.append(neighbour)
              queue.append(neighbour)
   print("\n")

if __name__ == '__main__':
   bfs(visited, graph, 'A')