经典算法python代码实现

来源：互联网发布：sql 判断是否在一天内编辑：程序博客网时间：2024/06/07 02:48

之前学算法经常不求甚解，懒癌发作不敲代码不实践，到头来自己挖的坑还是得自己填，我会陆续更新代码，本文大量代码来自互联网，能找到出处的我会尽量贴上出处

广度优先搜索、深度优先搜索

http://www.cnblogs.com/yupeng/p/3414736.html#commentform

class graph():    def __init__(self,*arg,**kwargs):        self.node_neighbors={}        self.visited={}    def add_nodes(self,nodelist):        for node in nodelist:            self.add_node(node)    def add_node(self,node):        if node not in self.node_neighbors.keys:            self.node_neighbors[node]=[]    def add_edge(self,edge):        u,v=edge        if (u not in self.node_neighbors[v]) and (v not in self.node_neighbors[u]):            self.node_neighbors[u].append(v)            if u!=v:                self.node_neighbors[v].append(u)    def depth_first_search(self,root=None):        self.visited={}        order=[]        def dfs(n):            self.visited[n]=True            order.append(n)            for node in self.node_neighbors[n]:                if node not in self.visited:                    dps(node)        if root:            dps(root)        for n in self.node_neighbors.keys:            if n not in self.visited:                dps(n)        print(order)        return order    def breadth_first_search(self,root=None):        self.visited={}        order=[]        queue=[]        def bfs():            while(len(queue)>0):                node = queue.pop(0)                self.visited[node]=True                for n in self.node_neighbors[node]:                    if not n in self.visited and not n in queue:                        order.append(n)                        queue.append(n)        if root:            queue.append(root)            order.append(root)            bfs()        for node in self.nodes():            if not node in self.visited:                queue.append(node)                order.append(node)                bfs()        print (order)        return orderif __name__ == '__main__':    g = Graph()g.add_nodes([i+1 for i in range(8)])g.add_edge((1, 2))g.add_edge((1, 3))g.add_edge((2, 4))g.add_edge((2, 5))g.add_edge((4, 8))g.add_edge((5, 8))g.add_edge((3, 6))g.add_edge((3, 7))g.add_edge((6, 7))print ("nodes:", g.node_neighbors)order = g.breadth_first_search(1)order = g.depth_first_search(1)

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