def test_pop(self):
s = ArrayStack()
s.push(1)
self.assertEqual(s.pop(), 1)
s.push(2)
s.push(3)
s.pop()
self.assertEqual(s.top(), 2)
def three_stack(R: ArrayStack, S: ArrayStack, T: ArrayStack):
R_len = len(R)
while not S.is_empty():
R.push(S.pop())
while not T.is_empty():
R.push(T.pop())
while len(R) > R_len:
S.push(R.pop())
def reverse_list(items):
s = ArrayStack()
for item in items:
s.push(item)
for i in range(len(items)):
items[i] = s.pop()
def stack_clear(s: ArrayStack) -> None:
if s.is_empty():
return
s.pop()
return stack_clear(s)
def transfer(S: ArrayStack, T: ArrayStack) -> None:
while not S.is_empty():
T.push(S.pop())