资 源 简 介
题目
The
15-puzzle has been around for over 100 years; even if you don"t know it by that
name, you"ve seen it. It is constructed with 15 sliding tiles, each with a
number from 1 to 15 on it, and all packed into a 4 by 4 frame with one tile
missing. Let"s call the missing tile "x"; the object of the puzzle is to
arrange the tiles so that they are ordered as:
1
2 3 4
5
6 7 8
9 10 11 12
13 14 15 x
where the only legal operation is to exchange "x" with one of the tiles with
which it shares an edge. As an example, the following sequence of moves solves
a slightly scrambled puzzle:
