mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-30 16:31:08 +00:00
bc8df6de31
* [pre-commit.ci] pre-commit autoupdate updates: - [github.com/astral-sh/ruff-pre-commit: v0.2.2 → v0.3.2](https://github.com/astral-sh/ruff-pre-commit/compare/v0.2.2...v0.3.2) - [github.com/pre-commit/mirrors-mypy: v1.8.0 → v1.9.0](https://github.com/pre-commit/mirrors-mypy/compare/v1.8.0...v1.9.0) * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci --------- Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
157 lines
3.6 KiB
Python
157 lines
3.6 KiB
Python
"""A Queue using a linked list like structure"""
|
|
|
|
from __future__ import annotations
|
|
|
|
from collections.abc import Iterator
|
|
from typing import Any
|
|
|
|
|
|
class Node:
|
|
def __init__(self, data: Any) -> None:
|
|
self.data: Any = data
|
|
self.next: Node | None = None
|
|
|
|
def __str__(self) -> str:
|
|
return f"{self.data}"
|
|
|
|
|
|
class LinkedQueue:
|
|
"""
|
|
>>> queue = LinkedQueue()
|
|
>>> queue.is_empty()
|
|
True
|
|
>>> queue.put(5)
|
|
>>> queue.put(9)
|
|
>>> queue.put('python')
|
|
>>> queue.is_empty()
|
|
False
|
|
>>> queue.get()
|
|
5
|
|
>>> queue.put('algorithms')
|
|
>>> queue.get()
|
|
9
|
|
>>> queue.get()
|
|
'python'
|
|
>>> queue.get()
|
|
'algorithms'
|
|
>>> queue.is_empty()
|
|
True
|
|
>>> queue.get()
|
|
Traceback (most recent call last):
|
|
...
|
|
IndexError: dequeue from empty queue
|
|
"""
|
|
|
|
def __init__(self) -> None:
|
|
self.front: Node | None = None
|
|
self.rear: Node | None = None
|
|
|
|
def __iter__(self) -> Iterator[Any]:
|
|
node = self.front
|
|
while node:
|
|
yield node.data
|
|
node = node.next
|
|
|
|
def __len__(self) -> int:
|
|
"""
|
|
>>> queue = LinkedQueue()
|
|
>>> for i in range(1, 6):
|
|
... queue.put(i)
|
|
>>> len(queue)
|
|
5
|
|
>>> for i in range(1, 6):
|
|
... assert len(queue) == 6 - i
|
|
... _ = queue.get()
|
|
>>> len(queue)
|
|
0
|
|
"""
|
|
return len(tuple(iter(self)))
|
|
|
|
def __str__(self) -> str:
|
|
"""
|
|
>>> queue = LinkedQueue()
|
|
>>> for i in range(1, 4):
|
|
... queue.put(i)
|
|
>>> queue.put("Python")
|
|
>>> queue.put(3.14)
|
|
>>> queue.put(True)
|
|
>>> str(queue)
|
|
'1 <- 2 <- 3 <- Python <- 3.14 <- True'
|
|
"""
|
|
return " <- ".join(str(item) for item in self)
|
|
|
|
def is_empty(self) -> bool:
|
|
"""
|
|
>>> queue = LinkedQueue()
|
|
>>> queue.is_empty()
|
|
True
|
|
>>> for i in range(1, 6):
|
|
... queue.put(i)
|
|
>>> queue.is_empty()
|
|
False
|
|
"""
|
|
return len(self) == 0
|
|
|
|
def put(self, item: Any) -> None:
|
|
"""
|
|
>>> queue = LinkedQueue()
|
|
>>> queue.get()
|
|
Traceback (most recent call last):
|
|
...
|
|
IndexError: dequeue from empty queue
|
|
>>> for i in range(1, 6):
|
|
... queue.put(i)
|
|
>>> str(queue)
|
|
'1 <- 2 <- 3 <- 4 <- 5'
|
|
"""
|
|
node = Node(item)
|
|
if self.is_empty():
|
|
self.front = self.rear = node
|
|
else:
|
|
assert isinstance(self.rear, Node)
|
|
self.rear.next = node
|
|
self.rear = node
|
|
|
|
def get(self) -> Any:
|
|
"""
|
|
>>> queue = LinkedQueue()
|
|
>>> queue.get()
|
|
Traceback (most recent call last):
|
|
...
|
|
IndexError: dequeue from empty queue
|
|
>>> queue = LinkedQueue()
|
|
>>> for i in range(1, 6):
|
|
... queue.put(i)
|
|
>>> for i in range(1, 6):
|
|
... assert queue.get() == i
|
|
>>> len(queue)
|
|
0
|
|
"""
|
|
if self.is_empty():
|
|
raise IndexError("dequeue from empty queue")
|
|
assert isinstance(self.front, Node)
|
|
node = self.front
|
|
self.front = self.front.next
|
|
if self.front is None:
|
|
self.rear = None
|
|
return node.data
|
|
|
|
def clear(self) -> None:
|
|
"""
|
|
>>> queue = LinkedQueue()
|
|
>>> for i in range(1, 6):
|
|
... queue.put(i)
|
|
>>> queue.clear()
|
|
>>> len(queue)
|
|
0
|
|
>>> str(queue)
|
|
''
|
|
"""
|
|
self.front = self.rear = None
|
|
|
|
|
|
if __name__ == "__main__":
|
|
from doctest import testmod
|
|
|
|
testmod()
|