Python实现常见算法[3]——汉罗塔递归

#!/usr/bin/python

# define three list var.

z1 = [1,2,3,4,5,6,7,"1st zhu"]

z2 = ["2st zhu"]

z3 = ["3st zhu"]

counter = 0

def HANLTA(n, a, b, c):

    global counter

    if n==1:

        counter = counter +1

        c.insert(0,a[0])

        del a[0]

        return

    else:

        HANLTA(n-1, a, c, b)

        counter = counter +1

        c.insert(0,a[0])

        del a[0]

        HANLTA(n-1,b,a,c)

HANLTA(7, z1, z2, z3)

print z1

print z2

print z3

print counter