八皇后问题 -- python面向对象解法

 # 【8*8棋盘八皇后问题】

 class Queen:
     def __init__(self, row, col):
         self.row = row
         self.col = col
         self.pos = (row + 1, col + 1)

     def check(self, chess_board):
         '''检查当前位置是否可放置皇后，默认每行只放一个皇后'''
         # 检测列
         for i in range(8):
             if chess_board.board[i][self.col] == 0:
                 return False
         # 检测两个斜向
         for i in range(-7, 8):
             if 0 <= self.row + i < 8 and 0 <= self.col + i < 8 and chess_board.board[self.row + i][self.col + i] == 0:
                 return False
             elif 0 <= self.row + i < 8 and 0 <= self.col - i < 8 and chess_board.board[self.row + i][self.col - i] == 0:
                 return False
         return True

 class Chess_Board:
     # 棋盘  无皇后为1，有皇后为0
     board = [[1 for i in range(8)] for i in range(8)]

     def print_board(self):
         '''可视化打印棋盘'''
         print('---------------------------------')
         for i in range(8):
             for j in range(8):
                 if self.board[i][j] == 1:
                     print(' +', end='') # + 无皇后
                 else:
                     print(' @', end='') # @ 表示皇后
             print()
         print('---------------------------------')

 def solve():
     '''返回结果棋盘对象和皇后对象列表'''

     def check_nextline(queens, chess_board):
         '''已知所有皇后坐标，判断下一行是否有位置'''
         next_col = len(queens)
         if next_col < 8:
             for i in range(8):
                 queen = Queen(next_col, i)
                 if queen.check(chess_board):
                     queens.append(queen)
                     chess_board.board[queen.row][queen.col] = 0
                     # chess_board.print_board() # 监控实现过程
                     return True
         return False

     queens = [] # 存储已放到棋盘上的皇后对象的列表
     chess_board = Chess_Board() # 创建唯一棋盘对象
     queen = Queen(0, 0)
     queens.append(queen)
     chess_board.board[queen.row][queen.col] = 0
     while 1:
         # 如果下一行没有位置，就将该行的皇后向右移一格
         while not check_nextline(queens, chess_board):
             queen = queens.pop(-1)
             chess_board.board[queen.row][queen.col] = 1
             while queen.col == 7:
                 queen = queens.pop(-1)
                 chess_board.board[queen.row][queen.col] = 1

             queen = Queen(queen.row, queen.col + 1)
             # 如果皇后右移后与原先皇后冲突，则继续右移
             while not queen.check(chess_board):
                 if queen.col < 7:
                     queen = Queen(queen.row, queen.col + 1)
                 else:
                     while queen.col == 7:
                         queen = queens.pop(-1)
                         chess_board.board[queen.row][queen.col] = 1

                     queen = Queen(queen.row, queen.col + 1)
             queens.append(queen)
             chess_board.board[queen.row][queen.col] = 0

         # 放满8个皇后之后跳出while 1循环
         if len(queens) == 8:
             break
     return queens, chess_board

 def main():
     '''主函数'''
     queens, chess_board = solve()
     for queen in queens:
         print(queen.pos)
     chess_board.print_board()

 if __name__ == "__main__":
     main()