ToH.py

'''
def hanoi(numberofdisks, source, helper, target):
    if numberofdisks>0:
        print("-",numberofdisks)
        #Move n-1 to helper
        hanoi(numberofdisks-1, source, target, helper)
        print("--",hanoi(numberofdisks-1, source, target, helper))
        #Move disk from source to peg
        if source:
            target.append(source.pop())
            print("---",target)
        hanoi(numberofdisks-1, helper, source, target)
        print("----",hanoi(numberofdisks-1, helper, source, target))
source = [4,3,2,1]
target = []
helper = []
hanoi(len(source), source, helper, target)
print( source, helper, target)
'''
def hanoi(n, source, helper, target):
    print ("hanoi(", n, source, helper, target, " called")
    if n >1:
        # move tower of size n - 1 to helper:
        hanoi(n - 1, source, target, helper)
        # move disk from source peg to target peg
        if source[0]:
            disk = source[0].pop()
            print ("moving " + str(disk) + " from " + source[1] + " to " + target[1])
            target[0].append(disk)
        # move tower of size n-1 from helper to target
        hanoi(n - 1, helper, source, target)

source = ([2,1], "source")
target = ([], "target")
helper = ([], "helper")
hanoi(len(source[0]),source,helper,target)

print( source, helper, target)