class deque(object):
def __init__(self, iterable=(), maxsize=-1):
if not hasattr(self, 'data'):
self.left = self.right = 0
self.data = {}
self.maxsize = maxsize
self.extend(iterable)
def append(self, x):
self.data[self.right] = x
self.right += 1
if self.maxsize != -1 and len(self) > self.maxsize:
self.popleft()
def appendleft(self, x):
self.left -= 1
self.data[self.left] = x
if self.maxsize != -1 and len(self) > self.maxsize:
self.pop()
def pop(self):
if self.left == self.right:
raise IndexError('cannot pop from empty deque')
self.right -= 1
elem = self.data[self.right]
del self.data[self.right]
return elem
def popleft(self):
if self.left == self.right:
raise IndexError('cannot pop from empty deque')
elem = self.data[self.left]
del self.data[self.left]
self.left += 1
return elem
def clear(self):
self.data.clear()
self.left = self.right = 0
def extend(self, iterable):
for elem in iterable:
self.append(elem)
def extendleft(self, iterable):
for elem in iterable:
self.appendleft(elem)
def rotate(self, n=1):
if self:
n %= len(self)
for i in xrange(n):
self.appendleft(self.pop())
def __getitem__(self, i):
if i < 0:
i += len(self)
try:
return self.data[i + self.left]
except KeyError:
raise IndexError
def __setitem__(self, i, value):
if i < 0:
i += len(self)
try:
self.data[i + self.left] = value
except KeyError:
raise IndexError
def __delitem__(self, i):
size = len(self)
if not (-size <= i < size):
raise IndexError
data = self.data
if i < 0:
i += size
for j in xrange(self.left+i, self.right-1):
data[j] = data[j+1]
self.pop()
def __len__(self):
return self.right - self.left
def __cmp__(self, other):
if type(self) != type(other):
return cmp(type(self), type(other))
return cmp(list(self), list(other))
def __repr__(self, _track=[]):
if id(self) in _track:
return '...'
_track.append(id(self))
r = 'deque(%r)' % (list(self),)
_track.remove(id(self))
return r
def __getstate__(self):
return (tuple(self),)
def __setstate__(self, s):
self.__init__(s[0])
def __hash__(self):
raise TypeError
def __copy__(self):
return self.__class__(self)
def __deepcopy__(self, memo={}):
from copy import deepcopy
result = self.__class__()
memo[id(self)] = result
result.__init__(deepcopy(tuple(self), memo))
return result
