DFS-python

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,s):
    stack=[]                         #将BFS中的queue全部改成stack
    stack.append(s)
    seen=set()
    seen.add(s)
    while(len(stack)>0):
        vertex=stack.pop()       #后进先出，弹出末尾
        nodes=graph[vertex]
        for w in nodes:
            if w not in seen:
                seen.add(w)
                stack.append(w)
        print(vertex)

BFS(graph,"A")