递归，汉诺塔游戏

def hanoi(n,a,b,c):
    if n==1:
        print(n,a+'->'+c)
    else:
        hanoi(n-1,a,c,b)
        print(n,a+'->'+c)
        hanoi(n-1,b,a,c)

hanoi(7,'A','B','C')