python实现Floyd算法
发布时间:2020-12-17 07:35:39 所属栏目:Python 来源:网络整理
导读:下面是用Python实现Floyd算法的代码,供大家参考,具体内容如下 # -*- coding: utf-8 -*- """ Created on Thu Jul 13 14:56:37 2017 @author: linzr """ ## 表示无穷大 INF_val = 9999 class Floyd_Path(): def __init__(self,node,node_map,path_map): self
下面是用Python实现Floyd算法的代码,供大家参考,具体内容如下 # -*- coding: utf-8 -*- """ Created on Thu Jul 13 14:56:37 2017 @author: linzr """ ## 表示无穷大 INF_val = 9999 class Floyd_Path(): def __init__(self,node,node_map,path_map): self.node = node self.node_map = node_map self.node_length = len(node_map) self.path_map = path_map self._init_Floyd() def __call__(self,from_node,to_node): self.from_node = from_node self.to_node = to_node return self._format_path() def _init_Floyd(self): for k in range(self.node_length): for i in range(self.node_length): for j in range(self.node_length): tmp = self.node_map[i][k] + self.node_map[k][j] if self.node_map[i][j] > tmp: self.node_map[i][j] = tmp self.path_map[i][j] = self.path_map[i][k] print '_init_Floyd is end' def _format_path(self): node_list = [] temp_node = self.from_node obj_node = self.to_node print("the shortest path is: %d")%(self.node_map[temp_node][obj_node]) node_list.append(self.node[temp_node]) while True: node_list.append(self.node[self.path_map[temp_node][obj_node]]) temp_node = self.path_map[temp_node][obj_node] if temp_node == obj_node: break; return node_list def set_node_map(node_map,node_list,path_map): for i in range(len(node)): ## 对角线为0 node_map[i][i] = 0 for x,y,val in node_list: node_map[node.index(x)][node.index(y)] = node_map[node.index(y)][node.index(x)] = val path_map[node.index(x)][node.index(y)] = node.index(y) path_map[node.index(y)][node.index(x)] = node.index(x) if __name__ == "__main__": node = ['A','B','C','D','E','F','G'] node_list = [('A',9),('A',10),'G',15),('B',2),('G',3),12),('C',1),('E',7)] ## node_map[i][j] 存储i到j的最短距离 node_map = [[INF_val for val in xrange(len(node))] for val in xrange(len(node))] ## path_map[i][j]=j 表示i到j的最短路径是经过顶点j path_map = [[0 for val in xrange(len(node))] for val in xrange(len(node))] ## set node_map set_node_map(node_map,path_map) ## select one node to obj node,e.g. A --> D(node[0] --> node[3]) from_node = node.index('A') to_node = node.index('E') Floydpath = Floyd_Path(node,path_map) path = Floydpath(from_node,to_node) print path 运行结果为: (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |