在python中用字典制作邻接列表来解决图形问题的替代方法？(就像c++中的vector<vector<int>>)

Question

在python中，我注意到有人使用 defaultdict(list) 或类似的东西.你怎么写的 list<int> adj[n] 或 vector<vector<int>> adj(n) 在python中？

不会使用字典，而字典基本上是由 unordered_maps 使大图的运行时间变慢？

Answer 1

用OOPs的方式！取自于 图表和它的表现形式. 感谢@DarrylG提供的!

# A class to represent the adjacency list of the node 
class AdjNode: 
    def __init__(self, data): 
        self.vertex = data 
        self.next = None


# A class to represent a graph. A graph 
# is the list of the adjacency lists. 
# Size of the array will be the no. of the 
# vertices "V" 
class Graph: 
    def __init__(self, vertices): 
        self.V = vertices 
        self.graph = [None] * self.V 

    # Function to add an edge in an undirected graph 
    def add_edge(self, src, dest): 
        # Adding the node to the source node 
        node = AdjNode(dest) 
        node.next = self.graph[src] 
        self.graph[src] = node 

        # Adding the source node to the destination as 
        # it is the undirected graph 
        node = AdjNode(src) 
        node.next = self.graph[dest] 
        self.graph[dest] = node