def test_node():
our_node = Node("first")
assert our_node.data == "first"
assert our_node.next is None
our_other_node = Node("second", our_node)
assert our_other_node.next is our_node
def test_3(self):
""" check that nodes are added to top of stack """
s = Stack()
n1 = Node(5)
n2 = Node(4)
s.push(n1)
s.push(n2)
self.assertEqual(s.top._value, 4)
def test_7(self):
""" check that len returns length of stack """
s = Stack()
n1 = Node(5)
n2 = Node(4)
s.push(n1)
s.push(n2)
self.assertEqual(len(s), 2)
def test_3(self):
"""test that second item pushed to stack is top"""
n1 = Node('A')
n2 = Node('B')
s = Stack()
s.push(n1)
s.push(n2)
self.assertEqual(s.top._value, 'B')
def test_4(self):
"""test that pop returns top of stack"""
n1 = Node('A')
n2 = Node('B')
s = Stack()
s.push(n1)
s.push(n2)
returned = s.pop()
self.assertEqual(returned._value, 'B')
def test_5(self):
"""test that top of stack changes after pop"""
n1 = Node('A')
n2 = Node('B')
s = Stack()
s.push(n1)
s.push(n2)
s.pop()
self.assertEqual(s.top._value, 'A')
def test_4(self):
""" check that nodes are removed from top of stack """
s = Stack()
n1 = Node(5)
n2 = Node(4)
s.push(n1)
s.push(n2)
s.pop()
self.assertEqual(s.top._value, 5)
def push(self, data: int):
super().push(data)
if self.min_stack.head:
head: Node = self.min_stack.head
node: Node = Node(head.data) if head.data <= data else Node(data)
node.next = self.min_stack.head
self.min_stack.head = node
else:
self.min_stack.head = Node(data)
def push(self, item):
if not self.stack_now:
self._addStack()
node = Node(item)
node.next = self.stack_now.top
self.stack_now.top = node
self.stack_now_size += 1
if self._checkIfFull():
self._archiveStack()
def push(self, item):
if not self.stack_now:
self._addStack()
node = Node(item)
node.next = self.stack_now.top
self.stack_now.top = node
self.stack_now_size += 1
if self._checkIfFull():
self._archiveStack()
def push(self, item):
if self.top:
min_so_far = self.mins[-1]
if min_so_far > item:
self.mins.append(item)
else:
self.mins.append(min_so_far)
else:
self.mins.append(item)
node = Node(item)
node.next = self.top
self.top = node
def enqueue(self, value):
new_node = Node(value)
if self.back is None:
self.front = self.back = new_node
else:
self.back.next_ = new_node
self.back = new_node
def push(self, value):
if not self.head:
self.head = Node(value)
self.min_stack.add_to_stack(value)
else:
# value is MIN
if value < self.get_min():
self.min_stack.add_to_stack(value)
# take node at head
current_head = self.head
# assign new node to head with next_node = previous head
self.head = Node(value)
self.head.next_node = current_head
self.length += 1
def test_6(self):
"""test that using pop on one node stack works"""
n1 = Node('A')
s = Stack()
s.push(n1)
s.pop()
self.assertEqual(s.top, None)
def test_end_to_end(self):
print('Test: Empty stack')
stack = Stack()
self.assertAlmostEqual(len(stack), 0)
self.assertEqual(stack.peek(), None)
self.assertEqual(stack.pop(), None)
print('Test: One element')
top = Node(5)
stack = Stack(top)
self.assertEqual(len(stack), 1)
self.assertEqual(stack.pop(), 5)
self.assertEqual(stack.peek(), None)
print('Test: More than one element')
stack = Stack()
stack.push(1)
stack.push(2)
stack.push(3)
self.assertEqual(len(stack), 3)
self.assertEqual(stack.pop(), 3)
self.assertEqual(len(stack), 2)
self.assertEqual(stack.peek(), 2)
self.assertEqual(stack.pop(), 2)
self.assertEqual(len(stack), 1)
self.assertEqual(stack.peek(), 1)
self.assertEqual(stack.isEmpty(), False)
self.assertEqual(stack.pop(), 1)
self.assertEqual(len(stack), 0)
self.assertEqual(stack.peek(), None)
self.assertEqual(stack.isEmpty(), True)
print('Success: test_end_to_end')
def __init__(self, values):
if len(values) == 0:
self.top = None
return
self.top = Node(values[-1])
if len(values) == 1:
self.bottom = self.top
prev = self.top
for val in values[1::-1]:
node = Node(val)
node.prev = prev
prev.next = node
prev = node
self.bottom = node
def test_end_to_end(self):
print('Test: Empty stack')
stack = Stack()
assert_equal(stack.peek(), None)
assert_equal(stack.pop(), None)
print('Test: One element')
top = Node(5)
stack = Stack(top)
assert_equal(stack.pop(), 5)
assert_equal(stack.peek(), None)
print('Test: More than one element')
stack = Stack()
stack.push(1)
stack.push(2)
stack.push(3)
assert_equal(stack.pop(), 3)
assert_equal(stack.peek(), 2)
assert_equal(stack.pop(), 2)
assert_equal(stack.peek(), 1)
assert_equal(stack.is_empty(), False)
assert_equal(stack.pop(), 1)
assert_equal(stack.peek(), None)
assert_equal(stack.is_empty(), True)
print('Success: test_end_to_end')
def __init__(self, value=None):
if value == None:
self.head = None
self.tail = None
self.length = 0
else:
self.head = Node(value)
self.tail = self.head
self.length = 1
def add(self, value):
new_node = Node(value)
if self.head == None:
self.head = new_node
self.tail = new_node
else:
self.tail.next = new_node
self.tail = new_node
self.length += 1
def trans(self, exp):
"""把算术表达式做成后缀式的"""
postexp = []
op = Stack()
op.push(Node("="))
# pass是跳过的意思，可以用来写大概框架
# ++++++++++
# 如果按下面的写，会有错
# 在for循环中的while让j+=1，并不能改变while外面j的值
# for j in range(len(exp)):
j = 0
# 遍历表达式
while (j < len(exp)):
# 前面要加上self
# 如果是运算数，就直接将其放在postexp中，继续向下遍历，直到不是运算数，在postexp后面加上#
if (self.isOP(exp[j]) is False):
# 在while循环里面加上j<len(exp)，因为当循环到字符串的最后一个字符时，再向下遍历，已经超出字符串，
# 下标越界，再进行exp[j].isdigit()时，则会出现IndexError: string index out of range
while (j < len(exp) and exp[j].isdigit()):
postexp.append(exp[j])
j += 1
postexp.append("#")
# 如果是运算符，就将该运算符和op栈顶的运算符进行优先级比较
else:
# 这里是op.top.data(str类型)，不是op.top(node类型)
judge = self.precede(op.top.data, exp[j])
# 如果op栈顶运算符的优先级高，将栈顶运算符出栈并将其存入postexp中
if judge == -1:
postexp.append(op.pop())
# 如果op栈顶运算符和该运算符的优先级一样，栈顶运算符出栈
if judge == 0:
op.pop()
j += 1
# 如果op栈顶运算符的优先级低，将该运算符入op栈
if judge == 1:
op.push(Node(exp[j]))
j += 1
# exp扫描完，op栈还有除了 “=”以外的运算符，将其所有存入postexp
while (op.top.data != "="):
postexp.append(op.pop())
# +++++++++++
return "".join(postexp)
def push(self, data: int) -> Optional[SetOfStacks]:
print(data, end=" ")
if self.count_current == self.stack_size:
if self.current_stack == 0:
print("Stack Overflow")
return None
else:
self.count_current = 1
self.current_stack -= 1
self.head[self.current_stack] = Node(data)
else:
node: Node = Node(data)
if self.head[self.current_stack]:
node.next = self.head[self.current_stack]
self.head[self.current_stack] = node
self.count_current += 1
return self
def push(self, data: int):
node = Node(data)
if not self.head:
self.head = node
else:
head = self.head
while head.next:
head = head.next
head.next = node
def computVal(self, postexp):
"""计算后缀式的值"""
vstack = Stack()
n = []
d = 0
for char in postexp:
isop = self.isOP(char)
# ++++++++++++
# 运算数
if not isop:
if (char != "#"):
d = 10 * d + int(char)
else:
vstack.push(Node(d))
d = 0
# 运算符
else:
num1 = vstack.pop()
num2 = vstack.pop()
vstack.push(Node(self.cal(num1, num2, char)))
# ++++++++++++
return vstack.top.data
def balanced_parentheses(expression):
open_parentheses = "({["
closed_parethese = ")}]"
for brackets in expression:
if brackets in open_parentheses:
bracts = Node(brackets)
obj.push(brackets)
elif brackets in closed_parentheses:
obj.pop()
if obj.is_empty():
print("given expression is balanced")
else:
print("given expression is not balance")
def push(self, val):
new = Node(val)
new.next = self.top
self.top.prev = new
self.top = new
def test_1(self):
""" check node creation """
n1 = Node(5)
self.assertEqual(n1.value(), 5)
def test_6(self):
""" check that returns value if only one node to pop """
s = Stack()
n1 = Node(5)
s.push(n1)
self.assertEqual(s.pop(), 5)
def __init__(self, content=None, next=None, previous=None):
self.previous = previous
Node.__init__(self, content, next)
def test_1(self):
"""test creating a node"""
n1 = Node('A')
self.assertEqual(n1._value, 'A')
def test_2(self):
""" check that nodes are added to stack """
s = Stack()
n1 = Node(5)
s.push(n1)
self.assertEqual(s.top._value, 5)
def create_nodes():
n1, n2, n3 = Node(1), Node(2), Node('a')
return n1, n2, n3
def __init__(self, top=None):
super(StackMin, self).__init__(top)
self.minimum_stack = Stack(Node(sys.maxsize))