astar

代码说明：

  A*算法 1、将开始节点放入开放列表(开始节点的F和G值都视为0) 2、重复以下步骤: 在开放列表中查找具有最小F值的节点,并把查找到的节点作为当前节点 把当前节点从开放列表删除, 加入到封闭列表. (A* algorithm 1, will begin to node placed in the and opening up list of (the began to node of the F and G values ​ ​ are regarded as 0) 2, repeat the the following steps: to Find a the has a the the smallest F value of the node in the the and opening up list of, and put Find a to the node as the current node current node is removed from the open list, added to the closed list.)