Print adjacency list Python

PROGRAM TO PRINT THE ADJACENCY LIST

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

 

    # Function to print the graph

    def print_graph(self):

        for i in range(self.V):

            print("Adjacency list of vertex {}\n head".format(i), end="")

            temp = self.graph[i]

            while temp:

                print(" -> {}".format(temp.vertex), end="")

                temp = temp.next

            print(" \n")

 

 

# Driver program to the above graph class

if __name__ == "__main__":

    V = 5

    graph = Graph(V)

    graph.add_edge(0, 1)

    graph.add_edge(0, 4)

    graph.add_edge(1, 2)

    graph.add_edge(1, 3)

    graph.add_edge(1, 4)

    graph.add_edge(2, 3)

    graph.add_edge(3, 4)

 

    graph.print_graph()







OUTPUT:

 Adjacency list of vertex 0
 head -> 1-> 4

 Adjacency list of vertex 1
 head -> 0-> 2-> 3-> 4

 Adjacency list of vertex 2
 head -> 1-> 3

 Adjacency list of vertex 3
 head -> 1-> 2-> 4

 Adjacency list of vertex 4
 head -> 0-> 1-> 3

CREDITS: https://www.geeksforgeeks.org/graph-and-its-representations/