1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
| """
递归回溯法：叫称为试探法，按选优条件向前搜索，当搜索到某一步，发现原先选择并不优或达不到目标时，就退回一步重新选择，比较经典的问题包括骑士巡逻、八皇后和迷宫寻路等。
"""
import sys
import time
SIZE = 5
total = 0
def print_board(board):
for row in board:
for col in row:
print(str(col).center(4), end='')
print()
def patrol(board, row, col, step=1):
if row >= 0 and row < SIZE and \
col >= 0 and col < SIZE and \
board[row][col] == 0:
board[row][col] = step
if step == SIZE * SIZE:
global total
total += 1
print(f'第{total}种走法: ')
print_board(board)
patrol(board, row - 2, col - 1, step + 1)
patrol(board, row - 1, col - 2, step + 1)
patrol(board, row + 1, col - 2, step + 1)
patrol(board, row + 2, col - 1, step + 1)
patrol(board, row + 2, col + 1, step + 1)
patrol(board, row + 1, col + 2, step + 1)
patrol(board, row - 1, col + 2, step + 1)
patrol(board, row - 2, col + 1, step + 1)
board[row][col] = 0
def main():
board = [[0] * SIZE for _ in range(SIZE)]
patrol(board, SIZE - 1, SIZE - 1)
if __name__ == '__main__':
main()
|
