def test_init(self):
stack = Stack()
self.assertEqual(stack.data, [])
stack = Stack(5)
self.assertEqual(stack.data, [5])
stack = Stack([1, 2, 3])
self.assertEqual(stack.data, [1, 2, 3])
def test_size(self):
stack = Stack()
self.assertEqual(stack.size(), 0)
stack.push(1)
self.assertEqual(stack.size(), 1)
stack.push(2)
self.assertEqual(stack.size(), 2)
def test_peek(self):
stack = Stack()
self.assertRaises(Exception, stack.peek)
stack.push(5)
stack.push(4)
self.assertEqual(stack.peek(), 4)
self.assertEqual(stack.size(), 2)
stack.pop()
self.assertEqual(stack.peek(), 5)
self.assertEqual(stack.size(), 1)
def test_push(self):
stack = Stack()
stack.push(5)
self.assertEqual(stack.data, [5])
self.assertEqual(stack.size(), 1)
stack.push(5)
self.assertEqual(stack.data, [5, 5])
self.assertEqual(stack.size(), 2)
def pre_order_iterative(node):
if node == None:
return
stack1 = Stack()
stack1.push(node)
while not stack1.is_empty():
temp = stack1.pop()
print temp,
if temp.right:
stack1.push(temp.right)
if temp.left:
stack1.push(temp.left)
def size_of_tree_stack(node):
if node == None:
return
stack1 = Stack()
stack1.push(node)
size = 0
while not stack1.is_empty():
temp = stack1.pop()
size += 1
if temp.left:
stack1.push(temp.left)
if temp.right:
stack1.push(temp.right)
return size
def in_order_iterative(node):
if node == None:
return
stack1 = Stack()
#stack1.push(node)
curr = node
done = False
while not done:
if curr != None:
stack1.push(curr)
curr = curr.left
else:
if not stack1.is_empty():
curr = stack1.pop()
print curr,
curr = curr.right
else:
done = True
def bst_or_not(node):
if node == None:
return
stack1 = Stack()
stack1.push(node)
#import ipdb; ipdb.set_trace()
while not stack1.is_empty():
temp = stack1.pop()
if not temp.left is None:
if temp.left.data < temp.data :
stack1.push(temp.left)
else:
return False
if not temp.right is None:
if temp.right.data > temp.data :
stack1.push(temp.right)
else:
return False
return True
def has_path_sum_pair(node, sum):
if node == None:
return
stack1 = Stack()
lista = []
stack1.push(node)
lista.append(node.data)
while not stack1.is_empty():
temp = stack1.pop()
if not temp.left is None:
#if temp.left.data < temp.data :
stack1.push(temp.left)
lista.append(temp.left.data)
if not temp.right is None:
stack1.push(temp.right)
lista.append(temp.right.data)
for i in range(len(lista)):
if sum-lista[i] in lista:
return True
return False
def print_linked_list_in_reverse(start):
if(start == None):
return
stack = Stack()
temp = start
while(temp != None):
stack.push(temp)
temp = temp.next
while(not stack.is_empty()):
print stack.pop(),
def test_is_empty(self):
stack = Stack()
self.assertTrue(stack.is_empty())
stack.push(1)
self.assertFalse(stack.is_empty())
def post_order_iterative_two_stack(node):
if node == None:
return
stack1 = Stack()
stack2 = Stack()
stack1.push(node)
while not stack1.is_empty():
curr = stack1.pop()
stack2.push(curr)
if curr.left:
stack1.push(curr.left)
if curr.right:
stack1.push(curr.right)
while not stack2.is_empty():
temp = stack2.pop()
print temp,
def post_order_iterative_one_stack(node):
if node == None:
return
stack1 = Stack()
stack1.push(node)
prev = None
while not stack1.is_empty():
curr = stack1.top()
if (prev == None or prev.right == curr or prev.left ==curr):
# go down the Tree
if curr.left != None:
stack1.push(curr.left)
elif curr.right != None:
stack1.push(curr.right)
else:
print stack1.pop()
elif curr.left == prev:
if curr.right != None:
stack1.push(curr.right)
else:
print stack1.pop()
elif curr.right == prev:
print stack1.pop()
prev = curr