class StackSLL(object):
def __init__(self):
self.store = SinglyLinkedList()
def push(self, value):
"""
adds the value to the front of the list
"""
self.store.addToFront(value)
def pop(self):
"""
removes the value from the front of the list and returns it
"""
value = self.peek()
self.store.removeFromFront()
return value
def peek(self):
"""
returns the next value to be popped
"""
return self.store.get(0)
def isEmpty(self):
"""
returns True if the value is empty
"""
return self.store.isEmpty()
class QueueSLL(object):
def __init__(self):
self.store = SinglyLinkedList()
def enqueue(self, value):
"""
adds the value to the back of the list
"""
self.store.addToBack(value)
def dequeue(self):
"""
removes the value from the front of the list
"""
if self.isEmpty():
raise IndexError("the queue is empty")
value = self.peek()
self.store.removeFromFront()
return value
def peek(self):
"""
returns the first value to be dequeued
"""
if self.isEmpty():
raise IndexError("the queue is empty")
return self.store.get(0)
def isEmpty(self):
return self.store.getSize() == 0
