Breadth-First Path Finding, Python 3

Language: Layout:

"""
Breadth-First Path Finding
"""

class Node:
    def __init__(self, val):
        self.val = val
        self.neighbors = {}
        
    def __repr__(self):
        return str(self.val)
        
    def __str__(self):
        return str(self.val) + ": " + str([neighbor for neighbor in self.neighbors.keys()])

class Graph:
    def __init__(self):
        self.nodesList = []
        self.nodesCount = 0
        
    def addNode(self, val):
        newnode = Node(val)
        if newnode not in self.nodesList:
            self.nodesList.append(newnode)
            self.nodesCount += 1
        return newnode
            
    def addEdge(self, source, destination, cost = 0):
        if source not in self.nodesList:
            self.nodesList.append(source)
            self.nodesCount += 1
        
        if destination not in self.nodesList:
            self.nodesList.append(destination)
            self.nodesCount += 1
            
        source.neighbors[destination] = 1
        
            
    def size(self):
        return self.nodesCount
            
    def __str__(self):
        result = ''
        for node in self.nodesList:
            result += str(node) + "\n"
        return result

graph = Graph()
node1 = graph.addNode( 10 )
node2 = graph.addNode( 20 )
node3 = graph.addNode( 30 )

graph.addEdge(node1, node2)
graph.addEdge(node1, node3)
graph.addEdge(node2, node3)
graph.addEdge(node3, node1)

print(graph)
print('Size = ' + str(graph.size()))

[ + ] Show input
Absolute running time: 0.15 sec, cpu time: 0.04 sec, memory peak: 8 Mb, absolute service time: 0.16 sec