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[mypy] fix type annotations in data_structures/queue/circular_queue_linked_list.py (#5749)

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* [mypy] fix type annotations in circular_queue_linked_list

* Remove 10 blank lines

Co-authored-by: Christian Clauss <cclauss@me.com>
This commit is contained in:
Dylan Buchi 2021-11-02 07:09:46 -03:00 committed by GitHub
parent 3c8fec1316
commit 24731b078c
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1 changed files with 24 additions and 13 deletions
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37
data_structures/queue/circular_queue_linked_list.py
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@ -1,6 +1,8 @@
# Implementation of Circular Queue using linked lists # Implementation of Circular Queue using linked lists
# https://en.wikipedia.org/wiki/Circular_buffer # https://en.wikipedia.org/wiki/Circular_buffer
from __future__ import annotations
from typing import Any from typing import Any
@ -18,8 +20,8 @@ class CircularQueueLinkedList:
""" """
def __init__(self, initial_capacity: int = 6) -> None: def __init__(self, initial_capacity: int = 6) -> None:
self.front = None self.front: Node | None = None
self.rear = None self.rear: Node | None = None
self.create_linked_list(initial_capacity) self.create_linked_list(initial_capacity)
def create_linked_list(self, initial_capacity: int) -> None: def create_linked_list(self, initial_capacity: int) -> None:
@ -27,7 +29,7 @@ class CircularQueueLinkedList:
self.front = current_node self.front = current_node
self.rear = current_node self.rear = current_node
previous_node = current_node previous_node = current_node
for i in range(1, initial_capacity): for _ in range(1, initial_capacity):
current_node = Node() current_node = Node()
previous_node.next = current_node previous_node.next = current_node
current_node.prev = previous_node current_node.prev = previous_node
@ -49,9 +51,14 @@ class CircularQueueLinkedList:
>>> cq.is_empty() >>> cq.is_empty()
True True
""" """
return self.front == self.rear and self.front.data is None
def first(self) -> Any: return (
self.front == self.rear
and self.front is not None
and self.front.data is None
)
def first(self) -> Any | None:
""" """
Returns the first element of the queue Returns the first element of the queue
>>> cq = CircularQueueLinkedList() >>> cq = CircularQueueLinkedList()
@ -74,7 +81,7 @@ class CircularQueueLinkedList:
'b' 'b'
""" """
self.check_can_perform_operation() self.check_can_perform_operation()
return self.front.data return self.front.data if self.front else None
def enqueue(self, data: Any) -> None: def enqueue(self, data: Any) -> None:
""" """
@ -92,11 +99,13 @@ class CircularQueueLinkedList:
... ...
Exception: Empty Queue Exception: Empty Queue
""" """
if self.rear is None:
return
self.check_is_full() self.check_is_full()
if self.is_empty(): if not self.is_empty():
self.rear.data = data
else:
self.rear = self.rear.next self.rear = self.rear.next
if self.rear:
self.rear.data = data self.rear.data = data
def dequeue(self) -> Any: def dequeue(self) -> Any:
@ -117,6 +126,8 @@ class CircularQueueLinkedList:
Exception: Empty Queue Exception: Empty Queue
""" """
self.check_can_perform_operation() self.check_can_perform_operation()
if self.rear is None or self.front is None:
return
if self.front == self.rear: if self.front == self.rear:
data = self.front.data data = self.front.data
self.front.data = None self.front.data = None
@ -133,15 +144,15 @@ class CircularQueueLinkedList:
raise Exception("Empty Queue") raise Exception("Empty Queue")
def check_is_full(self) -> None: def check_is_full(self) -> None:
if self.rear.next == self.front: if self.rear and self.rear.next == self.front:
raise Exception("Full Queue") raise Exception("Full Queue")
class Node: class Node:
def __init__(self) -> None: def __init__(self) -> None:
self.data = None self.data: Any | None = None
self.next = None self.next: Node | None = None
self.prev = None self.prev: Node | None = None
if __name__ == "__main__": if __name__ == "__main__":