1. Graph representation using Adjacency Matrix

Graph Representation using Adjacency Matrix¶

• https://www.geeksforgeeks.org/graph-and-its-representations/
• https://www.geeksforgeeks.org/visualize-graphs-in-python/

In [1]:

import networkx as nx
import numpy as np
import matplotlib.pyplot as plt

import networkx as nx import numpy as np import matplotlib.pyplot as plt

Graph¶

Graph

0---1
|  /
| /
|/
2---3

Expected Matrix

[
    [0, 1, 1, 0]
    [1, 0, 1, 0]
    [1, 1, 0, 1]
    [0, 0, 1, 0]

]

Using Adjacency Matrix¶

In [2]:

def graph_using_adjacency_matrix(n=4):

    adjacency_matrix = [[0 for i in range(n)] for j in range(n)]

    for i in range(n):
        u, v = map(int, input().split())
        adjacency_matrix[u][v] = 1
        adjacency_matrix[v][u] = 1

    return np.array(adjacency_matrix)

def graph_using_adjacency_matrix(n=4): adjacency_matrix = [[0 for i in range(n)] for j in range(n)] for i in range(n): u, v = map(int, input().split()) adjacency_matrix[u][v] = 1 adjacency_matrix[v][u] = 1 return np.array(adjacency_matrix)

In [3]:

graph_using_adjacency_matrix()

graph_using_adjacency_matrix()

Out[3]:

array([[0, 1, 1, 0],
       [1, 0, 1, 0],
       [1, 1, 0, 1],
       [0, 0, 1, 0]])

Using NetworkX¶

In [26]:

class GraphVisualization:
    def __init__(self):

        # visual is a list which stores all
        # the set of edges that constitutes a
        # graph
        self.visual = []

    # addEdge function inputs the vertices of an
    # edge and appends it to the visual list
    def addEdge(self, a, b):
        temp = [a, b]
        self.visual.append(temp)

    # In visualize function G is an object of
    # class Graph given by networkx G.add_edges_from(visual)
    # creates a graph with a given list
    # nx.draw_networkx(G) - plots the graph
    # plt.show() - displays the graph
    def visualize(self):
        G = nx.Graph()
        G.add_edges_from(self.visual)
        nx.draw_networkx(G)
        plt.show()

class GraphVisualization: def __init__(self): # visual is a list which stores all # the set of edges that constitutes a # graph self.visual = [] # addEdge function inputs the vertices of an # edge and appends it to the visual list def addEdge(self, a, b): temp = [a, b] self.visual.append(temp) # In visualize function G is an object of # class Graph given by networkx G.add_edges_from(visual) # creates a graph with a given list # nx.draw_networkx(G) - plots the graph # plt.show() - displays the graph def visualize(self): G = nx.Graph() G.add_edges_from(self.visual) nx.draw_networkx(G) plt.show()

In [28]:

G = GraphVisualization()
G.addEdge(0, 1)
G.addEdge(0, 2)
G.addEdge(1, 2)
G.addEdge(2, 3)
G.visualize()

G = GraphVisualization() G.addEdge(0, 1) G.addEdge(0, 2) G.addEdge(1, 2) G.addEdge(2, 3) G.visualize()

In [ ]: