Module grscheller.datastructures.squeue
Module grscheller.datastructure.queue - queue based datastructures
Module implementing stateful FIFO data structures with amortized O(1) pushing & popping from the queue. Obtaining length (number of elements) of a queue is also a O(1) operation. Implemented with a Python List based circular array. Does not store None as a value.
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# Copyright 2023 Geoffrey R. Scheller
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Module grscheller.datastructure.queue - queue based datastructures
Module implementing stateful FIFO data structures with amortized O(1) pushing
& popping from the queue. Obtaining length (number of elements) of a queue is
also a O(1) operation. Implemented with a Python List based circular array.
Does not store None as a value.
"""
from __future__ import annotations
__all__ = ['SQueue']
__author__ = "Geoffrey R. Scheller"
__copyright__ = "Copyright (c) 2023 Geoffrey R. Scheller"
__license__ = "Appache License 2.0"
from typing import Any
from .core.queue import Queue
class SQueue(Queue):
"""Single sided queue datastructure. Will resize itself as needed.
None represents the absence of a value and ignored if pushed onto an SQueue.
"""
def __init__(self, *ds):
"""Construct a FIFO SQueue data structure."""
super().__init__(*ds)
def __str__(self):
return "<< " + " < ".join(map(str, self)) + " <<"
def copy(self) -> SQueue:
"""Return shallow copy of the SQueue in O(n) time & space complexity."""
squeue = SQueue()
squeue._carray = self._carray.copy()
return squeue
def push(self, *ds: Any) -> None:
"""Push data on rear of the SQueue & no return value."""
for d in ds:
if d != None:
self._carray.pushR(d)
def pop(self) -> Any:
"""Pop data off front of the SQueue."""
if len(self._carray) > 0:
return self._carray.popL()
else:
return None
def peakLastIn(self) -> Any:
"""Return last element pushed to the SQueue without consuming it"""
if len(self._carray) > 0:
return self._carray[-1]
else:
return None
def peakNextOut(self) -> Any:
"""Return next element ready to pop from the SQueue."""
if len(self._carray) > 0:
return self._carray[0]
else:
return None
if __name__ == "__main__":
pass
Classes
class SQueue (*ds)
-
Single sided queue datastructure. Will resize itself as needed. None represents the absence of a value and ignored if pushed onto an SQueue.
Construct a FIFO SQueue data structure.
Expand source code
class SQueue(Queue): """Single sided queue datastructure. Will resize itself as needed. None represents the absence of a value and ignored if pushed onto an SQueue. """ def __init__(self, *ds): """Construct a FIFO SQueue data structure.""" super().__init__(*ds) def __str__(self): return "<< " + " < ".join(map(str, self)) + " <<" def copy(self) -> SQueue: """Return shallow copy of the SQueue in O(n) time & space complexity.""" squeue = SQueue() squeue._carray = self._carray.copy() return squeue def push(self, *ds: Any) -> None: """Push data on rear of the SQueue & no return value.""" for d in ds: if d != None: self._carray.pushR(d) def pop(self) -> Any: """Pop data off front of the SQueue.""" if len(self._carray) > 0: return self._carray.popL() else: return None def peakLastIn(self) -> Any: """Return last element pushed to the SQueue without consuming it""" if len(self._carray) > 0: return self._carray[-1] else: return None def peakNextOut(self) -> Any: """Return next element ready to pop from the SQueue.""" if len(self._carray) > 0: return self._carray[0] else: return None
Ancestors
Methods
def copy(self) ‑> SQueue
-
Return shallow copy of the SQueue in O(n) time & space complexity.
Expand source code
def copy(self) -> SQueue: """Return shallow copy of the SQueue in O(n) time & space complexity.""" squeue = SQueue() squeue._carray = self._carray.copy() return squeue
def peakLastIn(self) ‑> Any
-
Return last element pushed to the SQueue without consuming it
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def peakLastIn(self) -> Any: """Return last element pushed to the SQueue without consuming it""" if len(self._carray) > 0: return self._carray[-1] else: return None
def peakNextOut(self) ‑> Any
-
Return next element ready to pop from the SQueue.
Expand source code
def peakNextOut(self) -> Any: """Return next element ready to pop from the SQueue.""" if len(self._carray) > 0: return self._carray[0] else: return None
def pop(self) ‑> Any
-
Pop data off front of the SQueue.
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def pop(self) -> Any: """Pop data off front of the SQueue.""" if len(self._carray) > 0: return self._carray.popL() else: return None
def push(self, *ds: Any) ‑> None
-
Push data on rear of the SQueue & no return value.
Expand source code
def push(self, *ds: Any) -> None: """Push data on rear of the SQueue & no return value.""" for d in ds: if d != None: self._carray.pushR(d)
Inherited members