节点定义

# 图节点结构
class Node:
	def __init__(self, value):
		self.value = value   # 节点值
		self.come = 0 		 # 入度
		self.out = 0         # 出度
		self.nexts = []      # 邻居节点
		self.edges = []      # 在节点为from的情况下，边的集合

边定义

class Edges:
	def __init__(self, weight, from, to):
		self.weight = weight   # 边的权重
        self.fro = fro         # 边的from节点
        self.to = to           # 边的to节点

图结构

class Graph:
	def __init__(self):
		self.nodes = {}   # 图的所有节点集合  字典形式：{节点编号：节点}
		self.edges = []   # 图的边集合

图的实现

# 生成图结构
# matrix = [
#   [1,2,3],        ==>   里面分别代表权重, from节点, to节点
#   [...]
# ]
from Graph import Graph
from Node import Node
from Edge import Edge


def createGraph(matrix):
    graph = Graph()
    for edge in matrix:
        weight = edge[0]
        fro = edge[1]
        to = edge[2]
        if fro not in graph.nodes:
            graph.nodes[fro] = Node(fro)
        if to not in graph.nodes:
            graph.nodes[to] = Node(to)
        fromNode = graph.nodes[fro]
        toNode = graph.nodes[to]
        newEdge = Edge(weight, fromNode, toNode)
        fromNode.nexts.append(toNode)
        fromNode.out += 1
        toNode.come += 1
        fromNode.edges.append(newEdge)
        graph.edges.append(newEdge)
    return graph

原文：
https://www.cnblogs.com/icekx/p/915244a4.html