汉诺塔问题

移动步骤为h(n)=2h(n-1)+1步

代码实现：

def hannoi(n, a, b, c):
    if n > 0:
        hannoi(n - 1, a, c, b)
        print('moving from %s to %s' % (a, c))
        hannoi(n - 1, b, a, c)


hannoi(4, 'A', 'B', 'C')