def test_stack_is_empty():
s = Stack()
assert s.is_empty()
s.push(1)
assert not s.is_empty()
class MyQueue:
def __init__(self):
self.s1 = Stack()
self.s2 = Stack()
def add(self, data):
self.s1.push(data)
def remove(self):
if self.is_empty():
return
if not self.s2.is_empty():
return self.s2.pop()
current = self.s1.pop()
while not self.s1.is_empty():
self.s2.push(current)
current = self.s1.pop()
return current
def is_empty(self):
return self.s1.is_empty() and self.s2.is_empty()