def test_stack_push_pop():
el = 1
stack = Stack(5)
stack.push(el)
assert stack.size() == 1
assert stack.pop() == el
assert stack.size() == 0
class Queue:
def __init__(self):
self.s1 = Stack()
self.s2 = Stack()
def enqueue(self, val):
while self.s1.size() > 0:
self.s2.push(self.s1.pop())
self.s2.push(val)
while self.s2.size() > 0:
self.s1.push(self.s2.pop())
def dequeue(self):
return self.s1.pop()
def stack_reverse_string(input):
stk = Stack()
for elem in input:
stk.push(elem)
res = ""
while stk.size() > 0:
elem = stk.pop()
res += elem
return res
def matching_parens(input):
stk = Stack()
for elem in input:
if elem in paren_map.keys():
stk.push(elem)
else:
if stk.size() == 0:
return False
match = stk.pop()
if not paren_map[match] == elem:
return False
return True
def reverseString(mystr):
"""
Reverses the input string using Stack data structure
INPUT
-------
mystr : apple
RETURN
-------
elppa
"""
revStr = ''
temp = Stack()
for token in mystr:
temp.push(token)
for i in range(temp.size()):
revStr += temp.pop()
return revStr
class TestStack(TestCase):
def setUp(self):
super().setUp()
self.stack = Stack()
def test_pop(self):
self.stack.push(1)
self.stack.push(2)
self.assertEqual(self.stack.pop(), 2)
self.assertEqual(self.stack.pop(), 1)
def test_pop_empty(self):
self.assertIsNone(self.stack.pop())
def test_peek(self):
self.stack.push(1)
self.stack.push(2)
self.assertEqual(self.stack.peek(), 2)
self.stack.pop()
self.assertEqual(self.stack.peek(), 1)
def test_size(self):
self.stack.push(1)
self.stack.push(2)
self.assertEqual(self.stack.size(), 2)
def test_is_empty(self):
self.assertTrue(self.stack.is_empty())
self.stack.push(1)
self.assertFalse(self.stack.is_empty())
self.stack.pop()
