BFS & DFS

graph = {
    'A':['B','C'],
    'B':['A','C','D'],
    'C':['A','B','D','E'],
    'D':['B','C','E','F'],
    'E':['C','D'],
    'F':['D']
}
def BFS(graph,start):
    queue = []
    queue.append(start)
    seen = set()       #使用集合的效率要比使用list的效率高
    seen.add(start)
    while len(queue)>0:     #queue不为空的时候
        vertex = queue.pop(0)
        next_nodes = graph[vertex]
        for w in next_nodes:
            if w not in seen:
                queue.append(w)
                seen.add(w)     #将见过的添加进去
        print(vertex)
def DFS(graph,start):
    stack = []
    stack.append(start)
    seen = set()       #使用集合的效率要比使用list的效率高
    seen.add(start)
    while len(stack)>0:     #stack不为空的时候
        vertex = stack.pop()        #由于是栈所以弹出最后一个元素
        next_nodes = graph[vertex]
        for w in next_nodes:
            if w not in seen:
                stack.append(w)
                seen.add(w)     #将见过的添加进去
        print(vertex)
print('BFS')
BFS(graph,'E')
print('*'*100)
print('DFS')
DFS(graph,'E')