adjacency-matrix.py

# A simple representation of graph using Adjacency Matrix
class Graph:
    def __init__(self, numvertex):
        self.adjMatrix = [[-1] * numvertex for x in range(numvertex)]
        self.numvertex = numvertex
        self.vertices = {}
        self.verticeslist = [0] * numvertex

    def set_vertex(self, vtx, id):
        if 0 <= vtx <= self.numvertex:
            self.vertices[id] = vtx
            self.verticeslist[vtx] = id

    def set_edge(self, frm, to, cost=0):
        frm = self.vertices[frm]
        to = self.vertices[to]
        self.adjMatrix[frm][to] = cost
        # for directed graph do not add this
        self.adjMatrix[to][frm] = cost

    def get_vertex(self):
        return self.verticeslist

    def get_edges(self):
        edges = []
        for i in range(self.numvertex):
            for j in range(self.numvertex):
                if self.adjMatrix[i][j] != -1:
                    edges.append(
                        (
                            self.verticeslist[i],
                            self.verticeslist[j],
                            self.adjMatrix[i][j],
                        )
                    )
        return edges

    def get_matrix(self):
        return self.adjMatrix

    @staticmethod
    def display():
        mat = G.get_matrix()
        print("\n[\n", end=" ")
        for i in range(len(mat)):
            print(mat[i])
        print("\n]", end=" ")


G = Graph(6)
G.set_vertex(0, "a")
G.set_vertex(1, "b")
G.set_vertex(2, "c")
G.set_vertex(3, "d")
G.set_vertex(4, "e")
G.set_vertex(5, "f")
G.set_edge("a", "e", 10)
G.set_edge("a", "c", 20)
G.set_edge("c", "b", 30)
G.set_edge("b", "e", 40)
G.set_edge("e", "d", 50)
G.set_edge("f", "e", 60)
print("Vertices of Graph")
print(G.get_vertex())
print("Edges of Graph")
print(G.get_edges())
print("Adjacency Matrix of Graph")
print(G.get_matrix())
G.display()