python 递归-汉诺塔

# 汉诺塔
a = "A"
b = "B"
c = "C"
def hano(a, b, c, n):
    if n == 1:
        print("{} --> {}".format(a, c))
    if n == 2:
        print("{} --> {}".format(a, c))
        print("{} --> {}".format(a, b))
        print("{} --> {}".format(b, c))
        return None
    hano(a, b, c, n - 1)
    print("{} --> {}".format(a, c))
    hano(b, a, c, n - 1)

hano(a, b, c, 5)

A --> C
A --> B
B --> C
A --> C
B --> C
B --> A
A --> C
A --> C
B --> C
B --> A
A --> C
B --> C
A --> C
A --> B
B --> C
A --> C
B --> C
B --> A
A --> C
B --> C
A --> C
A --> B
B --> C
B --> C
A --> C
A --> B
B --> C
A --> C
B --> C
B --> A
A --> C