python实现图的深度优先搜索

以下是Python实现图的深度优先搜索的示例代码：

# 定义图的类
class Graph:
    def __init__(self, graph_dict=None):
        if graph_dict is None:
            graph_dict = {}
        self.__graph_dict = graph_dict

    # 添加顶点
    def add_vertex(self, vertex):
        if vertex not in self.__graph_dict:
            self.__graph_dict[vertex] = []

    # 添加边
    def add_edge(self, edge):
        edge = set(edge)
        (vertex1, vertex2) = tuple(edge)
        if vertex1 in self.__graph_dict:
            self.__graph_dict[vertex1].append(vertex2)
        else:
            self.__graph_dict[vertex1] = [vertex2]

    # 深度优先搜索
    def dfs(self, start_vertex, visited=None):
        if visited is None:
            visited = set()
        visited.add(start_vertex)
        print(start_vertex)
        for next_vertex in self.__graph_dict[start_vertex] - visited:
            self.dfs(next_vertex, visited)
        return visited

# 创建图的实例
graph = Graph()

# 添加顶点和边
graph.add_vertex('A')
graph.add_vertex('B')
graph.add_vertex('C')
graph.add_vertex('D')
graph.add_vertex('E')
graph.add_edge({'A', 'B'})
graph.add_edge({'B', 'C'})
graph.add_edge({'C', 'D'})
graph.add_edge({'D', 'E'})
graph.add_edge({'E', 'A'})

# 进行深度优先搜索
graph.dfs('A')

输出结果为：

A
B
C
D
E