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 {}
 head".format(i), end="")            temp = self.graph[i]            while temp:                print(" -> {}".format(temp.vertex), end="")                temp = temp.next            print(" 
")