N皇后问题是算法中回溯法应用的一个经典案例 回溯算法也叫试探法，它是一种系统地搜索问题的解的方法。回溯算法的基本思想是：从一条路往前走，能进则进，不能进则退回来，换一条路再试。 -N queens problem is backtracking algorithm applied a classic case of backtracking algorithm, also called heuristics, which is a systematic method for solvi