基于Dragonboard 410c的 A路径搜索算法实现

     在http://blog.csdn.net/andymfc/article/details/60960202中，我们介绍了A算法的的基本原理，这里我们参考网上已有的算法，给出了具体的路径搜索算法的实现，如下：

    # -*-coding:utf-8 -*-

class DijkstraExtendPath():

  def __init__(self, node_map):

    self.node_map = node_map

    self.node_length = len(node_map)

    self.used_node_list = []

    self.collected_node_dict = {}

  def __call__(self, from_node, to_node):

    self.from_node = from_node

    self.to_node = to_node

    self._init_dijkstra()

    return self._format_path()

  def _init_dijkstra(self):

    self.used_node_list.append(self.from_node)

    self.collected_node_dict[self.from_node] = [0, -1]

    for index1, node1 in enumerate(self.node_map[self.from_node]):

      if node1:

        self.collected_node_dict[index1] = [node1, self.from_node]

    self._foreach_dijkstra()

  def _foreach_dijkstra(self):

    if len(self.used_node_list) == self.node_length - 1:

      return

    for key, val in self.collected_node_dict.items(): # 遍历已有权值节点

      if key not in self.used_node_list and key != to_node:

        self.used_node_list.append(key)

      else:

        continue

      for index1, node1 in enumerate(self.node_map[key]): # 对节点进行遍历

        # 如果节点在权值节点中并且权值大于新权值

        if node1 and index1 in self.collected_node_dict and self.collected_node_dict[index1][0] > node1 + val[0]:

          self.collected_node_dict[index1][0] = node1 + val[0] # 更新权值

          self.collected_node_dict[index1][1] = key

        elif node1 and index1 not in self.collected_node_dict:

          self.collected_node_dict[index1] = [node1 + val[0], key]

    self._foreach_dijkstra()

  def _format_path(self):

    node_list = []

    temp_node = self.to_node

    node_list.append((temp_node, self.collected_node_dict[temp_node][0]))

    while self.collected_node_dict[temp_node][1] != -1:

      temp_node = self.collected_node_dict[temp_node][1]

      node_list.append((temp_node, self.collected_node_dict[temp_node][0]))

    node_list.reverse()

    return node_list

def set_node_map(node_map, node, node_list):

  for x, y, val in node_list:

    node_map[node.index(x)][node.index(y)] = node_map[node.index(y)][node.index(x)] = val

if __name__ == "__main__":

  node = ['A', 'B', 'C', 'D', 'E', 'F', 'G']

  node_list = [('A', 'F', 9), ('A', 'B', 10), ('A', 'G', 15), ('B', 'F', 2),

         ('G', 'F', 3), ('G', 'E', 12), ('G', 'C', 10), ('C', 'E', 1),

         ('E', 'D', 7)]

  node_map = [[0 for val in xrange(len(node))] for val in xrange(len(node))]

  set_node_map(node_map, node, node_list)

  # A -->; D

  from_node = node.index('A')

  to_node = node.index('D')

  dijkstrapath = DijkstraPath(node_map)

  path = dijkstrapath(from_node, to_node)

  print path