八皇后问题是一个古老而著名的问题，是回溯算法的典型例题。该问题是十九世纪著名的数学家高斯1850年提出：在8X8格的国际象棋上摆放八个皇后，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。-Eight queens problem is an old and well-known problems, backtracking algorithm is a typical example. The problem is that the famous 19th century mathematician Gauss, 1850: placed in a 8X8 grid chess the eight queen, so that it can not attack each other, that is, any two queens can not be in the same line in the same column or diagonally online, and asked how many kinds of pendulum method.