Python/data_structures/queue/queue_on_pseudo_stack.py
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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
2024-03-13 07:52:41 +01:00

60 lines
1.5 KiB
Python

"""Queue represented by a pseudo stack (represented by a list with pop and append)"""
from typing import Any
class Queue:
def __init__(self):
self.stack = []
self.length = 0
def __str__(self):
printed = "<" + str(self.stack)[1:-1] + ">"
return printed
"""Enqueues {@code item}
@param item
item to enqueue"""
def put(self, item: Any) -> None:
self.stack.append(item)
self.length = self.length + 1
"""Dequeues {@code item}
@requirement: |self.length| > 0
@return dequeued
item that was dequeued"""
def get(self) -> Any:
self.rotate(1)
dequeued = self.stack[self.length - 1]
self.stack = self.stack[:-1]
self.rotate(self.length - 1)
self.length = self.length - 1
return dequeued
"""Rotates the queue {@code rotation} times
@param rotation
number of times to rotate queue"""
def rotate(self, rotation: int) -> None:
for _ in range(rotation):
temp = self.stack[0]
self.stack = self.stack[1:]
self.put(temp)
self.length = self.length - 1
"""Reports item at the front of self
@return item at front of self.stack"""
def front(self) -> Any:
front = self.get()
self.put(front)
self.rotate(self.length - 1)
return front
"""Returns the length of this.stack"""
def size(self) -> int:
return self.length