皇后问题 在n×n格的国际象棋上摆放n个皇后，使其不能互相攻击，即任意两个皇后都不能处于同一行、同一列或同一斜线上，问有多少种摆法。-N × n queen problem in grid placing n chess queens on, so that it can not attack each other, that any two Queens can not in the same row, same column or on the same diagonal, asked