class Queue(object):
"""Create queue data structure."""
def __init__(self):
"""Initalize a Queue."""
self._que = Dll()
def enqueue(self, val):
"""Add an item to the queue."""
self._que.push(val)
def dequeue(self):
"""Remove item from queue."""
return self._que.shift()
def peek(self):
"""Returns next value in queue without dequeueing it."""
if self._que.tail is not None:
return self._que.tail.value
return None
def size(self):
"""Get length of queue."""
return self._que.__len__()
class Deque(object):
"""Create deque data structure."""
def __init__(self):
"""Initalize a Deque."""
self._que = Dll()
def append(self, val):
"""Add an item to the deque."""
self._que.push(val)
def appendleft(self, val):
"""Append value to the front of the deque."""
self._que.append(val)
def pop(self):
"""Pop value from end of the deque and returns it."""
return self._que.pop()
def popleft(self):
"""Pop value from front of the deque and return it."""
return self._que.shift()
def peek(self):
"""Return next value in deque without dequeueing it."""
if self._que.head is not None:
return self._que.head.value
return None
def peekleft(self):
"""Return value of popleft but leaves value in deque."""
if self._que.tail is not None:
return self._que.tail.value
return None
def size(self):
"""Get length of deque."""
return self._que.__len__()
