This notebook was prepared by Donne Martin. Source and license info is on GitHub.
Complexity:
%run ../../stacks_queues/stack/stack.py
class Hanoi(object):
def move_disks(self, num_disks, src, dest, buff):
if src is None or dest is None or buff is None:
raise TypeError('Cannot have a None input')
self._move_disks(num_disks, src, dest, buff)
def _move_disks(self, num_disks, src, dest, buff):
if num_disks == 0:
return
self.move_disks(num_disks - 1, src, buff, dest)
dest.push(src.pop())
self.move_disks(num_disks - 1, buff, dest, src)
%%writefile test_hanoi.py
import unittest
class TestHanoi(unittest.TestCase):
def test_hanoi(self):
hanoi = Hanoi()
num_disks = 3
src = Stack()
buff = Stack()
dest = Stack()
print('Test: None towers')
self.assertRaises(TypeError, hanoi.move_disks, num_disks, None, None, None)
print('Test: 0 disks')
hanoi.move_disks(num_disks, src, dest, buff)
self.assertEqual(dest.pop(), None)
print('Test: 1 disk')
src.push(5)
hanoi.move_disks(num_disks, src, dest, buff)
self.assertEqual(dest.pop(), 5)
print('Test: 2 or more disks')
for disk_index in range(num_disks, -1, -1):
src.push(disk_index)
hanoi.move_disks(num_disks, src, dest, buff)
for disk_index in range(0, num_disks):
self.assertEqual(dest.pop(), disk_index)
print('Success: test_hanoi')
def main():
test = TestHanoi()
test.test_hanoi()
if __name__ == '__main__':
main()
Overwriting test_hanoi.py
%run -i test_hanoi.py
Test: None towers Test: 0 disks Test: 1 disk Test: 2 or more disks Success: test_hanoi