熟悉和掌握启发式搜索的定义、估价函数和算法过程，并利用A*算法求解N数码难题，理解求解流程和搜索顺序。-Be familiar with and master the definition of heuristic search,　uation function and the algorithm process, and use the A* algorithm N digital problem, understand the solving process and the search order.