要求在国际象棋的棋盘上放置八个皇后，使其不能相互攻击，即任意两个皇后不能处于 棋盘的同一行、同一列和同一条对角线上。试问有多少种放法？-To place eight Queen on the chess board so that it can not attack each other, that any two of the Queen' s not in the board on the same line, same column and with a diagonal. Ho