摘要：
Follow up for N-Queens problem. Now, instead outputting board configurations, return the total number of distinct solutions. 思路： 典型8皇后，回溯法，验证是否能放皇后位置， 阅读全文
摘要：
The n-queens puzzle is the problem of placing n queens on an n×n chessboard such that no two queens attack each other. Given an integer n, return all 阅读全文