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