使用NetworkX有效地检查图中的路径是否有效？

import networkx as nx

# 创建一个有向图
G = nx.DiGraph()

# 添加节点和边
G.add_nodes_from([1, 2, 3, 4])
G.add_edges_from([(1, 2), (2, 3), (3, 4)])

# 检查路径的有效性
source = 1
target = 4

# 检查是否存在路径
has_path = nx.has_path(G, source, target)
print("是否存在路径：", has_path)

# 查找最短路径
try:
    shortest_path = nx.shortest_path(G, source, target)
    print("最短路径：", shortest_path)
except nx.NetworkXNoPath:
    print("路径不存在")

# 查找所有简单路径
all_simple_paths = nx.all_simple_paths(G, source, target)
print("所有简单路径：")
for path in all_simple_paths:
    print(path)

# 查找所有最短路径
all_shortest_paths = nx.all_shortest_paths(G, source, target)
print("所有最短路径：")
for path in all_shortest_paths:
    print(path)