class PseudoQueue:
"""
Requires a stack of nodes as its only parameter.
Creates an instance of a "PseudoQueue".
Initialized with two stacks.
"""
def __init__(self, stack_a):
self.stack_a = stack_a
self.stack_b = Stack()
def enqueue(self, value):
"""
Takes a value as an arguement.
Creates an instance of a node with its value being the value given as an arguement.
Adds the new node to the "end" of the PseudoQueue. Last in line. Top of stack_a.
"""
new_node = Node(value)
new_node.next = self.stack_a.top
self.stack_a.top = new_node
def dequeue(self):
"""
Has no parameters.
Removes the node from the "front" of the PseudoQueue. First in line. The bottom of stack_a.
"""
while self.stack_a.top:
value = self.stack_a.pop()
# new_node = Node(value)
self.stack_b.push(value)
result = self.stack_b.pop()
while self.stack_b.top:
value = self.stack_b.pop()
# new_node = Node(value)
self.stack_a.push(value)
return result
class PseudoQueue:
def __init__(self, stack_a):
self.stack_a = stack_a
self.stack_b = Stack()
def enqueue(self, value):
new_node = Node(value)
new_node.next = self.stack_a.top
self.stack_a.top = new_node
def dequeue(self):
while self.stack_a.top:
value = self.stack_a.pop()
# new_node = Node(value)
self.stack_b.push(value)
result = self.stack_b.pop()
while self.stack_b.top:
value = self.stack_b.pop()
# new_node = Node(value)
self.stack_a.push(value)
return result
def stack_of_four_nodes():
new_stack = Stack()
new_stack.push(1)
new_stack.push(2)
new_stack.push(3)
new_stack.push(4)
return new_stack
def empty_stack():
new_stack = Stack()
return new_stack
def stack_of_one():
new_stack = Stack()
new_stack.push('one')
return new_stack
def __init__(self, stack_a):
self.stack_a = stack_a
self.stack_b = Stack()
def __init__(self, stack_a):
self.stack_a = stack_a
self.stack_b = Stack()
def enqueue(self, value):
new_node = Node(value)
new_node.next = self.stack_a.top
self.stack_a.top = new_node
def dequeue(self):
while self.stack_a.top:
value = self.stack_a.pop()
# new_node = Node(value)
self.stack_b.push(value)
result = self.stack_b.pop()
while self.stack_b.top:
value = self.stack_b.pop()
# new_node = Node(value)
self.stack_a.push(value)
return result
if __name__ == "__main__":
stack_a = Stack()
stack_a.push(20)
stack_a.push(15)
stack_a.push(10)
queue = PsudoQueue(stack_a)
a = queue.dequeue()
print(a.value)