Representation of Graph

class Graph():
    def __init__(self, matrixSize):
        # fill the matrix with 0.
        self.adjacencyMatrix = []
        for i in range(matrixSize):
            self.adjacencyMatrix.append([0 for i in range(matrixSize)])
        self.matrixSize = matrixSize

    def addEdge(self, node1, node2):
        self.adjacencyMatrix[node1][node2] = 1
        self.adjacencyMatrix[node2][node1] = 1

    def deleteEdge(self, node1, node2):
        # if there is an edge between the two giving nodes
        if self.adjacencyMatrix[node1][node2] == 1 :
            self.adjacencyMatrix[node1][node2] = 0
            self.adjacencyMatrix[node2][node1] = 0

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")