图算法之广度优先遍历

class Graph(object):

    def __init__(self):

        self.nodeNeighbors={}#使用邻街表方式表示图

        self.visited={}

 

    def addNode(self,node):#单个添加节点

        if node not in self.nodeNeighbors.keys():

            self.nodeNeighbors[node]=[]

 

    def addNodes(self,*nodelist):#批量添加节点

        for node in nodelist:

            self.addNode(node)

 

    def addEdge(self,edge,var=1):#使用邻街表方式添加图（有向有权图）

        u,v=edge

        if u==v:

            return None

        if v not in self.nodeNeighbors[u]:

            self.nodeNeighbors[u].append([v,var])

            return 1

 

    def nodes(self):

        return self.nodeNeighbors.keys()

 

    def breathFirstSearch(self,root=None):#广度优先遍历算法

        queue=[]

        order=[]

        def bfs():

            while len(queue)>0:

                node=queue.pop(0)

                self.visited[node] = 1

                for n,v in self.nodeNeighbors[node]:

                    if n not in self.visited and n not in order:

                        queue.append(n)

                        order.append(n)

        if root:

            queue.append(root)

            order.append(root)

            bfs()

            for node in self.nodes():#如果节点未遍历完全重新遍历一遍节点 全部检查一遍

                if node not in self.visited:

                    queue.append(node)

                    order.append(node)

                    bfs()

        return order

 

if __name__=="__main__":

    g=Graph()

    g.addNodes(1,2,3,4,5)

    g.addEdge((1,2))

    g.addEdge((1,3))

    g.addEdge((1,5))

    g.addEdge((3,4))

    print g.breathFirstSearch(3)