# implementation of an undirected graph using Adjacency Matrix, with weighted or unweighted edges class Vertex: def __init__(self, n): self.name = n class Graph: vertices = {} edges = [] edge_indices = {} def add_vertex(self, vertex): if isinstance(vertex, Vertex) and vertex.name not in self.vertices: self.vertices[vertex.name] = vertex for row in self.edges: row.append(0) self.edges.append([0] * (len(self.edges)+1)) self.edge_indices[vertex.name] = len(self.edge_indices) return True else: return False def add_edge(self, u, v, weight=1): if u in self.vertices and v in self.vertices: self.edges[self.edge_indices[u]][self.edge_indices[v]] = weight self.edges[self.edge_indices[v]][self.edge_indices[u]] = weight return True else: return False def print_graph(self): for v, i in sorted(self.edge_indices.items()): print(v + ' ', end='') for j in range(len(self.edges)): print(self.edges[i][j], end='') print(' ') g = Graph() # print(str(len(g.vertices))) a = Vertex('A') g.add_vertex(a) g.add_vertex(Vertex('B')) for i in range(ord('A'), ord('K')): g.add_vertex(Vertex(chr(i))) edges = ['AB', 'AE', 'BF', 'CG', 'DE', 'DH', 'EH', 'FG', 'FI', 'FJ', 'GJ', 'HI'] for edge in edges: g.add_edge(edge[:1], edge[1:]) g.print_graph()