def _post_order(self, node):
"""
Utility method for computing post-order
of a binary tree using iterative algorithm.
"""
visit = []
tree, size = self.tree.tree, self.tree.size
s = Stack()
s.push(node)
last = OneDimensionalArray(int, size)
last.fill(False)
while not s.is_empty:
node = s.peek
l, r = tree[node].left, tree[node].right
cl, cr = l is None or last[l], r is None or last[r]
if cl and cr:
s.pop()
visit.append(tree[node])
last[node] = True
continue
if not cr:
s.push(r)
if not cl:
s.push(l)
return visit
def test_Stack():
s = Stack(implementation='array')
s1 = Stack()
assert _check_type(s, ArrayStack) is True
assert _check_type(s1, ArrayStack) is True
s2 = Stack(implementation='linked_list')
assert _check_type(s2, LinkedListStack) is True
assert raises(NotImplementedError, lambda: Stack(implementation=''))
def test_ArrayStack():
s = Stack(implementation='array')
s.push(1)
s.push(2)
s.push(3)
assert s.peek == 3
assert str(s) == '[1, 2, 3]'
assert s.pop() == 3
assert s.pop() == 2
assert s.pop() == 1
assert s.is_empty is True
assert raises(IndexError, lambda: s.pop())
_s = Stack(items=[1, 2, 3])
assert str(_s) == '[1, 2, 3]'
assert len(_s) == 3
def _in_order(self, node):
"""
Utility method for computing in-order
of a binary tree using iterative algorithm.
"""
visit = []
tree, size = self.tree.tree, self.tree.size
s = Stack()
while not s.is_empty or node is not None:
if node is not None:
s.push(node)
node = tree[node].left
else:
node = s.pop()
visit.append(tree[node])
node = tree[node].right
return visit
def _pre_order(self, node):
"""
Utility method for computing pre-order
of a binary tree using iterative algorithm.
"""
visit = []
tree, size = self.tree.tree, self.tree.size
s = Stack()
s.push(node)
while not s.is_empty:
node = s.pop()
visit.append(tree[node])
if tree[node].right is not None:
s.push(tree[node].right)
if tree[node].left is not None:
s.push(tree[node].left)
return visit
def _simple_path(self, key, root):
"""
Utility funtion to find the simple path between root and node.
Parameter
=========
key: Node.key
Key of the node to be searched
Returns
=======
path: list
"""
stack = Stack()
stack.push(root)
path = []
node_idx = -1
while not stack.is_empty:
node = stack.pop()
if self.tree[node].key == key:
node_idx = node
break
if self.tree[node].left:
stack.push(self.tree[node].left)
if self.tree[node].right:
stack.push(self.tree[node].right)
if node_idx == -1:
return path
while node_idx != 0:
path.append(node_idx)
node_idx = self.tree[node_idx].parent
path.append(0)
path.reverse()
return path
def test_Stack():
s = Stack(maxsize=3, top=0)
s.push(1)
s.push(2)
s.push(3)
assert s.top == 3
assert str(s) == '[1, 2, 3]'
assert raises(ValueError, lambda: s.push(4))
assert s.pop() == 3
assert s.pop() == 2
assert s.pop() == 1
assert s.top == 0
assert raises(ValueError, lambda: s.pop())
assert raises(ValueError, lambda: Stack())
assert raises(TypeError, lambda: Stack(maxsize=8, top=3.5))
assert raises(ValueError, lambda: Stack(maxsize=5, top=0, items=[1, 2, 3]))
assert raises(
ValueError,
lambda: Stack(maxsize=5, top=0, items=OneDimensionalArray(int, 6)))
assert raises(NotImplementedError,
lambda: Stack(implementation='', maxsize=5, top=0))
def test_LinkedListStack():
s = Stack(implementation='linked_list')
s.push(1)
s.push(2)
s.push(3)
assert s.peek.key == 3
assert str(s) == ("['(1, None)', '(2, None)', '(3, None)']")
assert s.pop().key == 3
assert s.pop().key == 2
assert s.pop().key == 1
assert s.is_empty is True
assert raises(IndexError, lambda: s.pop())
assert str(s) == '[]'
_s = Stack(implementation='linked_list', items=[1, 2, 3])
assert str(_s) == "['(1, None)', '(2, None)', '(3, None)']"
assert len(_s) == 3
s = Stack(implementation='linked_list', items=['a', None, type, {}])
assert len(s) == 4
assert s.size == 4
peek = s.peek
assert peek.key == s.pop().key
assert raises(TypeError, lambda: Stack(implementation='linked_list', items={0, 1}))
def test_Stack():
s = Stack()
s.push(1)
s.push(2)
s.push(3)
assert s.peek == 3
assert str(s) == '[1, 2, 3]'
assert s.pop() == 3
assert s.pop() == 2
assert s.pop() == 1
assert s.is_empty is True
assert raises(IndexError, lambda : s.pop())
_s = Stack(items=[1, 2, 3])
assert str(_s) == '[1, 2, 3]'
assert len(_s) == 3
assert raises(NotImplementedError, lambda: Stack(implementation=''))
s = Stack(implementation='linked_list')
s.push(1)
s.push(2)
s.push(3)
assert s.peek == 3
assert str(s) == '[3, 2, 1]'
assert s.pop().data == 3
assert s.pop().data == 2
assert s.pop().data == 1
assert s.is_empty is True
assert raises(IndexError, lambda : s.pop())
_s = Stack(implementation='linked_list',items=[1, 2, 3])
assert str(_s) == '[3, 2, 1]'
assert len(_s) == 3
s = Stack(implementation='linked_list',items=['a',None,type,{}])
assert len(s) == 4
assert s.size == 4
top = s.top
assert top.data == s.pop().data
peek = s.peek
assert peek == s.pop().data
assert raises(TypeError, lambda: Stack(implementation='linked_list', items={0, 1}))
def test_Stack():
s = Stack()
s.push(1)
s.push(2)
s.push(3)
assert s.peek == 3
assert str(s) == '[1, 2, 3]'
assert s.pop() == 3
assert s.pop() == 2
assert s.pop() == 1
assert s.is_empty is True
assert raises(ValueError, lambda : s.pop())
_s = Stack(items=[1, 2, 3])
assert str(_s) == '[1, 2, 3]'
assert raises(NotImplementedError, lambda: Stack(implementation=''))
