1 # 【8*8棋盘八皇后问题】
2
3 class Queen:
4 def __init__(self, row, col):
5 self.row = row
6 self.col = col
7 self.pos = (row + 1, col + 1)
8
9 def check(self, chess_board):
10 '''检查当前位置是否可放置皇后，默认每行只放一个皇后'''
11 # 检测列
12 for i in range(8):
13 if chess_board.board[i][self.col] == 0:
14 return False
15 # 检测两个斜向
16 for i in range(-7, 8):
17 if 0 <= self.row + i < 8 and 0 <= self.col + i < 8 and chess_board.board[self.row + i][self.col + i] == 0:
18 return False
19 elif 0 <= self.row + i < 8 and 0 <= self.col - i < 8 and chess_board.board[self.row + i][self.col - i] == 0:
20 return False
21 return True
22
23
24
25 class Chess_Board:
26 # 棋盘 无皇后为1，有皇后为0
27 board = [[1 for i in range(8)] for i in range(8)]
28
29 def print_board(self):
30 '''可视化打印棋盘'''
31 print('---------------------------------')
32 for i in range(8):
33 for j in range(8):
34 if self.board[i][j] == 1:
35 print(' +', end='') # + 无皇后
36 else:
37 print(' @', end='') # @ 表示皇后
38 print()
39 print('---------------------------------')
40
41
42
43 def solve():
44 '''返回结果棋盘对象和皇后对象列表'''
45
46 def check_nextline(queens, chess_board):
47 '''已知所有皇后坐标，判断下一行是否有位置'''
48 next_col = len(queens)
49 if next_col < 8:
50 for i in range(8):
51 queen = Queen(next_col, i)
52 if queen.check(chess_board):
53 queens.append(queen)
54 chess_board.board[queen.row][queen.col] = 0
55 # chess_board.print_board() # 监控实现过程
56 return True
57 return False
58
59
60 queens = [] # 存储已放到棋盘上的皇后对象的列表
61 chess_board = Chess_Board() # 创建唯一棋盘对象
62 queen = Queen(0, 0)
63 queens.append(queen)
64 chess_board.board[queen.row][queen.col] = 0
65 while 1:
66 # 如果下一行没有位置，就将该行的皇后向右移一格
67 while not check_nextline(queens, chess_board):
68 queen = queens.pop(-1)
69 chess_board.board[queen.row][queen.col] = 1
70 while queen.col == 7:
71 queen = queens.pop(-1)
72 chess_board.board[queen.row][queen.col] = 1
73
74 queen = Queen(queen.row, queen.col + 1)
75 # 如果皇后右移后与原先皇后冲突，则继续右移
76 while not queen.check(chess_board):
77 if queen.col < 7:
78 queen = Queen(queen.row, queen.col + 1)
79 else:
80 while queen.col == 7:
81 queen = queens.pop(-1)
82 chess_board.board[queen.row][queen.col] = 1
83
84 queen = Queen(queen.row, queen.col + 1)
85 queens.append(queen)
86 chess_board.board[queen.row][queen.col] = 0
87
88 # 放满8个皇后之后跳出while 1循环
89 if len(queens) == 8:
90 break
91 return queens, chess_board
92
93
94
95 def main():
96 '''主函数'''
97 queens, chess_board = solve()
98 for queen in queens:
99 print(queen.pos)
100 chess_board.print_board()
101
102
103 if __name__ == "__main__":
104 main()
