class SortedPriorityQueue(PriorityQueueBase):
def __init__(self):
self._data = PositionalList()
def __len__(self):
return len(self._data)
def add(self, k, v):
newest = self._Item(k, v)
walk = self._data.last()
while walk is not None and walk.element() > newest:
walk = self._data.before(walk)
if walk is None:
self._data.add_first(newest)
else:
self._data.add_after(walk, newest)
def min(self):
if self.is_empty():
raise ValueError('Priority queue is empty')
item = self._data.first().element()
return (item._key, item._value)
def remove_min(self):
if self.is_empty():
raise ValueError('Priority queue is empty')
item = self._data.delete(self._data.first())
return (item._key, item._value)
