对于拼图问题的基于java的A*算法实现。状态空间图中的节点用一个Node对象表示，图中出现的节点（包括已扩展的和未扩展的）存放在一个list（ArrayList的一个对象）中，A*算法运行完毕后，最优路径上的节点存放在pathArray(ArrayList的一个对象)中。程序维护两个变量head和tail，在list中两者之间的节点表示open表中的未扩展节点，list中head之前的属于closed表中的已扩展节点。-Puzzle java-based A* algorithm. State space graph node with a Node object, figure nodes (including extended and non-extended) stored in a List (ArrayList to an object), the A* algorithm has finished running, the optimal path node storage in pathArray (ArrayList to an object). The program maintains the head and tail of two variables between the two nodes represent unexpanded node in the open table list in the head before the closed table has been extended node in the list.