def min(self):
"""Return but do not remove (k, v) tuple with minimum key"""
if self.is_empty():
raise Empty('Priority queue is empty')
p = self._data.first()
item = p.element()
return (item._key, item._value)
def delete_last(self):
"""Remove and return the element from the back of the deque
Raise Empty exception if the deque is empty.
"""
if self.is_empty():
raise Empty("Deque is empty!")
return self._delete_node(self._tailer._prev)
def delete_first(self):
"""Remove and return the element from the front of the deque
Raise Empty exception if the deque is empty.
"""
if self.is_empty():
raise Empty("Deque is empty!")
return self._delete_node(self._header._next)
def dequeue(self):
"""Remove and return the first element if the queue(i.e., FIFO).
Raisee Empty exception if the dueue is empty"""
if self.is_empty():
raise Empty("Queue is empty")
node = self._data.remove_first()
return node.value
def top(self):
"""
Return (but not remove) at the top of the stack.
Raise Empty exception if the stack in empty.
Time Complexity: O(1)
"""
if self.is_empty():
raise Empty("Stack in empty!")
return self._data[-1]
def remove_min(self):
"""Remove and return (k ,v) tuple with minimum key.
Raise Empty exception if empty"""
if self.is_empty():
raise Empty('Priority queue is empty')
self._swap(0, len(self._data) - 1)
item = self._data.pop()
self._downheadp(0)
return (item._key, item._value)
def first(self):
"""Return the first value in the list.
Or raise Empty error if the list is empty.
Time complexity: O(1)
"""
if self._size == 0:
raise Empty('The list is empty!')
return self._header._next._element
def last(self):
"""Return the last value in the list.
Or raise Empty error if the list is empty.
Time complexity: O(1)
"""
if self._size == 0:
raise Empty('The list is empty!')
return self._tailer._prev._element
def pop(self):
"""
Remove and return the element from the top of the stack(LIFO)
Raise Empty exception if the stack is empty.
Time Complexity: O(1)*
"""
if self.is_empty():
raise Empty("Stack is empty!")
return self._data.pop()
def first(self):
"""
Return the first element.
Raise Empty Error if the queue is empty
Time complexity: O(1)
"""
if self.is_empty():
raise Empty("Queue is empty!")
return self._data[self._font]
def _find_min(self):
"""Return Position of item with minimum key"""
if self.is_empty():
raise Empty('Priority queue is empty')
small = self._data.first()
walk = self._data.after(small)
while walk is not None:
if walk.element() < small.element():
small = walk
walk = self._data.after(walk)
return small
def remove_last(self):
"""Remove the last node of the list
Time complexity: O(1)"""
if self.is_empty():
raise Empty("The list is empty!")
element = self.first()
self._tailer._prev._prev = self._tailer
self._tailer._prev = self._tailer._prev._prev
self._size -= 1
return element
def pop(self):
"""
Remove and return the element from the top of the stack(LIFO)
Raise Empty exception if the stack is empty.
Time Complexity: O(1)
"""
if self.is_empty():
raise Empty("Stack is empty!")
ele = self._data.tail.value
self._data.remove_last()
return ele
def remove_first(self):
"""
Remove the first element in the single linked list.
Or raise an empty error when there is no node in the list.
Time complexity: O(1)
"""
if self.is_empty():
raise Empty("The single linked list is empty")
answer = self.head
self.head = self.head.next
self.size -= 1
return answer
def remove_first(self):
"""
Remove the first node of the list.
Or raise an Empty error if the list is empty.
Time complexity: O(1)
"""
if self.is_empty():
raise Empty("The list is empty!")
element = self.first()
self._header._next._next._prev = self._header
self._header._next = self._header._next._next
self._size -= 1
return element
def delete_last(self):
"""
Remove and return the last element from deque.
"""
if self.is_empty():
raise Empty('Dequeue is empty!')
answer = self.last()
back = (self._font + self._size - 1) % len(self._data)
self._data[back] = None
self._size -= 1
# shrinks
if 0 < self._size < len(self._data) // 4:
self._resize(len(self._data) // 2)
return answer
def dequeue(self):
"""
Remove and return the first element.
Raise Empty error if queue is empty
Time complexity: O(1)*
Note that `*` means amortized.
"""
if self.is_empty():
raise Empty("Queue is empty!")
answer = self._data[self._font]
# help garbage collection
self._data[self._font] = None
self._font = (self._font + 1) % len(self._data)
self._size -= 1
# shrinks
if 0 < self._size < len(self._data) // 4:
self._resize(len(self._data) // 2)
return answer
def remove_last(self):
"""
Remove the last element in the single linked list.
Or raise an empty error when there is no node in the list.
Time complexity: O(n)
"""
if self.is_empty():
raise Empty("The single linked list is empty")
answer = self.tail
# when head = tail, we should change head too.
if self.size == 1:
self.head = None
self.tail = None
else:
pointer = self.head
while pointer.next != self.tail:
pointer = pointer.next
self.tail = pointer
self.tail.next = None
self.size -= 1
return answer
def first(self):
"""Return(but not remove) the element at the front of the queue
"""
if self.is_empty():
raise Empty("Deque is empty!")
return self._header._next._element
def remove_min(self):
"""Remove and return (k, v) tuple with minimum key"""
if self.is_empty():
raise Empty('Priority queue is empty')
item = self._data.delete(self._data.first())
return (item._key, item._value)
def min(self):
if self.is_empty():
raise Empty('Priority queue is empty')
item = self._data[0]
return (item._key, item._value)
def first(self):
"""Return(but do not remove) the element at the front if the queue"""
if self.is_empty():
raise Empty("Queue is empty")
return self._data.head.value
def last(self):
"""Return(but not remove) the element at the back of the deque
"""
if self.is_empty():
raise Empty("Deque is empty!")
return self._tailer._prev._element
