def __delitem__(self, k):
if not self.is_empty():
p = self._subtree_search(self.root(), k)
if k == p.key():
self.delete(p)
return
raise Empty('Tree is empty')
def __getitem__(self, k):
if self.is_empty():
raise Empty('Tree is empty')
else:
p = self._subtree_search(self.root(), k)
if k != p.key():
raise KeyError('Key Error: ' + repr(k))
return p.value()
def dequeue(self):
if self.is_empty():
raise Empty('Queue is empty')
removed = self._head._element
self._head = self._head._next
self._size -= 1
if self.is_empty():
self._tail = None
return removed
def find_gt(self, k):
if self.is_empty():
raise Empty("Tree is empty")
else:
p = self.find_position(k)
if not k < p.key():
p = self.after(p)
if p is None:
return None
else:
return (p.key(), p.value())
def find_lt(self, k):
if self.is_empty():
raise Empty("Tree is empty")
else:
p = self.find_position(k)
if not p.key() < k:
p = self.before(p)
if p is None:
return None
else:
return (p.key(), p.value())
def find_range(self, start_k, stop_k):
if not self.is_empty():
if start_k is None:
p = self.first()
else:
p = self.find_position(start_k)
if p.key() < start_k:
p = self.after(p)
while p is not None and (stop_k is None or p.key() < stop_k):
yield (p.key(), p.value())
p = self.after(p)
raise Empty("Tree is empty")
def first(self):
if self.is_empty():
raise Empty('Queue is empty')
return self._head._element
def find_max(self):
if self.is_empty():
raise Empty("Tree is empty")
else:
p = self.last()
return (p.key(), p.value())