蓝桥杯python：放格分割

题目：

全部代码：

def get_dir(x, y):
    global ans
    if x == 0 or x == n or y == 0 or y == n:
        ans += 1
        return
    for i in range(4):
        tx = x + directions[i][0]
        ty = y + directions[i][1]
        if arr[tx][ty] == 0:
            arr[tx][ty] = 1
            arr[n - tx][n - ty] = 1
            get_dir(tx, ty)
            arr[tx][ty] = 0
            arr[n - tx][n - ty] = 0
    return (ans / 4)


n = 6
ans = 0
arr = [[0] * (n + 1) for i in range(10)]
directions = [(-1, 0), (1, 0), (0, -1), (0, 1)]
arr[3][3] = 1
print(get_dir(n // 2, n // 2))  

>>> 509.0