def superstack(state):
if state == "default":
input_data = """12
push 4
pop
push 3
push 5
push 2
inc 3 1
pop
push 1
inc 2 2
push 4
pop
pop"""
instructions = input_data.strip().split("\n")[1:]
stack = Stack()
for instruction in instructions:
instruction = instruction.strip()
Manipulation.super_stack(stack, instruction)
else:
number_of_instructions = int(raw_input())
stack = Stack()
for i in xrange(number_of_instructions):
instruction = raw_input().strip()
Manipulation.super_stack(stack, instruction)
class StackWithMin(Stack):
"""Uses a secondary stack to keep track of minimum values."""
def __init__(self):
super().__init__()
self.min_stack = Stack()
def push(self, item):
if self.is_empty():
self.min_stack.push(item)
elif item <= self.min():
self.min_stack.push(item)
super().push(item)
def pop(self):
item = super().peek() # Throws an exception if empty
if self.min() == item:
self.min_stack.pop()
return super().pop()
def min(self):
if self.is_empty():
raise IndexError('Stack is empty.')
else:
return self.min_stack.peek()
def sort_stack_iterative(s1):
"""Sorts s1 interatively using a scondary stack.
Ascending sort: bigger items on top.
"""
s2 = Stack()
# Sort items in descending order in s2
while not s1.is_empty():
next_item = s1.pop()
count = 0
while not s2.is_empty() and next_item > s2.peek():
s1.push(s2.pop())
count += 1
s2.push(next_item)
while count > 0:
s2.push(s1.pop())
count -= 1
# Move items back to s1 and reverse the order to ascedning
while not s2.is_empty():
s1.push(s2.pop())
class TestTowersOfHanoi(unittest.TestCase):
def setUp(self):
self.s1 = Stack()
self.s2 = Stack()
self.s3 = Stack()
def test_one(self):
self.s1.push('a')
towers_of_hanoi(1, self.s1, self.s2, self.s3)
self.assertTrue(self.s1.is_empty())
self.assertTrue(self.s2.is_empty())
self.assertEqual(self.s3.size(), 1)
self.assertEqual(self.s3.pop(), 'a')
def test_three(self):
self.s1.push('a')
self.s1.push('b')
self.s1.push('c')
towers_of_hanoi(3, self.s1, self.s2, self.s3)
self.assertTrue(self.s1.is_empty())
self.assertTrue(self.s2.is_empty())
self.assertEqual(self.s3.size(), 3)
self.assertEqual(self.s3.pop(), 'c')
self.assertEqual(self.s3.pop(), 'b')
self.assertEqual(self.s3.pop(), 'a')
def setUp(self):
self.s1 = Stack()
self.s2 = Stack()
self.s3 = Stack()
def __init__(self):
super().__init__()
self.min_stack = Stack()
def setUp(self):
self.s = Stack()
class TestStack(unittest.TestCase):
def setUp(self):
self.s = Stack()
def test_init(self):
self.assertTrue(self.s.is_empty())
self.assertEqual(self.s.size(), 0)
def test_push_and_size(self):
no_of_pushes = 10
for i in range(no_of_pushes):
self.s.push(i)
self.assertFalse(self.s.is_empty())
self.assertEqual(self.s.size(), no_of_pushes)
def test_push_then_pop(self):
no_of_pushes = 10
for i in range(no_of_pushes):
self.s.push(i)
for i in range(no_of_pushes):
self.assertEqual(self.s.pop(), no_of_pushes - i - 1)
self.assertTrue(self.s.is_empty())
self.assertEqual(self.s.size(), 0)
def test_push_then_peek(self):
self.s.push(100)
size = self.s.size()
self.assertEqual(self.s.peek(), 100)
self.assertEqual(self.s.size(), size)
def test_pop_from_empty_stack(self):
self.assertRaises(IndexError, self.s.pop)
def test_peek_into_empty_stack(self):
self.assertRaises(IndexError, self.s.peek)
class TestSortStack(unittest.TestCase):
def setUp(self):
self.s1 = Stack()
self.s2 = Stack()
def test_iterative_sort_one(self):
self.s1.push(5)
sort_stack_iterative(self.s1)
self.assertEqual(self.s1.size(), 1)
self.assertEqual(self.s1.pop(), 5)
def test_iterative_sort_three_descending(self):
self.s1.push(3)
self.s1.push(2)
self.s1.push(1)
sort_stack_iterative(self.s1)
self.assertEqual(self.s1.size(), 3)
self.assertEqual(self.s1.pop(), 3)
self.assertEqual(self.s1.pop(), 2)
self.assertEqual(self.s1.pop(), 1)
def test_iterative_sort_three_mixed(self):
self.s1.push(3)
self.s1.push(1)
self.s1.push(2)
sort_stack_iterative(self.s1)
self.assertEqual(self.s1.size(), 3)
self.assertEqual(self.s1.pop(), 3)
self.assertEqual(self.s1.pop(), 2)
self.assertEqual(self.s1.pop(), 1)
def test_recursive_sort_one(self):
self.s1.push(5)
sort_stack_recursive(1, self.s1, self.s2)
self.assertEqual(self.s1.size(), 1)
self.assertEqual(self.s1.pop(), 5)
self.assertEqual(self.s2.size(), 0)
def test_recursive_sort_three_descending(self):
self.s1.push(3)
self.s1.push(2)
self.s1.push(1)
sort_stack_recursive(3, self.s1, self.s2)
self.assertEqual(self.s1.size(), 3)
self.assertEqual(self.s1.pop(), 3)
self.assertEqual(self.s1.pop(), 2)
self.assertEqual(self.s1.pop(), 1)
self.assertEqual(self.s2.size(), 0)
def test_recursive_sort_three_mixed(self):
self.s1.push(3)
self.s1.push(1)
self.s1.push(2)
sort_stack_recursive(3, self.s1, self.s2)
self.assertEqual(self.s1.size(), 3)
self.assertEqual(self.s1.pop(), 3)
self.assertEqual(self.s1.pop(), 2)
self.assertEqual(self.s1.pop(), 1)
self.assertEqual(self.s2.size(), 0)