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[mypy] Fix and add type annotations in data_structures/queue/double_ended_queue.py #5618

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Merged
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Oct 27, 2021
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[mypy] Fix and add type annotations in data_structures/queue/double_ended_queue.py #5618

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72 changes: 18 additions & 54 deletions data_structures/queue/double_ended_queue.py
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Original file line number Diff line number Diff line change
@@ -1,42 +1,32 @@
"""
Implementation of double ended queue.
"""
from __future__ import annotations

from dataclasses import dataclass
from typing import Any, Iterable


class Deque:
"""
Deque data structure.

Operations
----------
append(val: Any) -> None

appendleft(val: Any) -> None

extend(iter: Iterable) -> None

extendleft(iter: Iterable) -> None

pop() -> Any

popleft() -> Any


Observers
---------
is_empty() -> bool


Attributes
----------
_front: _Node
front of the deque a.k.a. the first element

_back: _Node
back of the element a.k.a. the last element

_len: int
the number of nodes
"""
Expand All @@ -51,13 +41,12 @@ class _Node:
"""

val: Any = None
next: "Deque._Node" = None
prev: "Deque._Node" = None
next: Deque._Node | None = None
prev: Deque._Node | None = None

class _Iterator:
"""
Helper class for iteration. Will be used to implement iteration.

Attributes
----------
_cur: _Node
Expand All @@ -66,10 +55,10 @@ class _Iterator:

__slots__ = ["_cur"]

def __init__(self, cur: "Deque._Node") -> None:
def __init__(self, cur: Deque._Node | None) -> None:
self._cur = cur

def __iter__(self) -> "Deque._Iterator":
def __iter__(self) -> Deque._Iterator:
"""
>>> our_deque = Deque([1, 2, 3])
>>> iterator = iter(our_deque)
Expand All @@ -95,9 +84,10 @@ def __next__(self) -> Any:

return val

def __init__(self, iterable: Iterable = None) -> None:
self._front = self._back = None
self._len = 0
def __init__(self, iterable: Iterable[Any] | None = None) -> None:
self._front: Any = None
self._back: Any = None
self._len: int = 0

if iterable is not None:
# append every value to the deque
Expand All @@ -108,7 +98,6 @@ def append(self, val: Any) -> None:
"""
Adds val to the end of the deque.
Time complexity: O(1)

>>> our_deque_1 = Deque([1, 2, 3])
>>> our_deque_1.append(4)
>>> our_deque_1
Expand All @@ -117,7 +106,6 @@ def append(self, val: Any) -> None:
>>> our_deque_2.append('c')
>>> our_deque_2
['a', 'b', 'c']

>>> from collections import deque
>>> deque_collections_1 = deque([1, 2, 3])
>>> deque_collections_1.append(4)
Expand All @@ -127,7 +115,6 @@ def append(self, val: Any) -> None:
>>> deque_collections_2.append('c')
>>> deque_collections_2
deque(['a', 'b', 'c'])

>>> list(our_deque_1) == list(deque_collections_1)
True
>>> list(our_deque_2) == list(deque_collections_2)
Expand All @@ -153,7 +140,6 @@ def appendleft(self, val: Any) -> None:
"""
Adds val to the beginning of the deque.
Time complexity: O(1)

>>> our_deque_1 = Deque([2, 3])
>>> our_deque_1.appendleft(1)
>>> our_deque_1
Expand All @@ -162,7 +148,6 @@ def appendleft(self, val: Any) -> None:
>>> our_deque_2.appendleft('a')
>>> our_deque_2
['a', 'b', 'c']

>>> from collections import deque
>>> deque_collections_1 = deque([2, 3])
>>> deque_collections_1.appendleft(1)
Expand All @@ -172,7 +157,6 @@ def appendleft(self, val: Any) -> None:
>>> deque_collections_2.appendleft('a')
>>> deque_collections_2
deque(['a', 'b', 'c'])

>>> list(our_deque_1) == list(deque_collections_1)
True
>>> list(our_deque_2) == list(deque_collections_2)
Expand All @@ -194,11 +178,10 @@ def appendleft(self, val: Any) -> None:
# make sure there were no errors
assert not self.is_empty(), "Error on appending value."

def extend(self, iter: Iterable) -> None:
def extend(self, iter: Iterable[Any]) -> None:
"""
Appends every value of iter to the end of the deque.
Time complexity: O(n)

>>> our_deque_1 = Deque([1, 2, 3])
>>> our_deque_1.extend([4, 5])
>>> our_deque_1
Expand All @@ -207,7 +190,6 @@ def extend(self, iter: Iterable) -> None:
>>> our_deque_2.extend('cd')
>>> our_deque_2
['a', 'b', 'c', 'd']

>>> from collections import deque
>>> deque_collections_1 = deque([1, 2, 3])
>>> deque_collections_1.extend([4, 5])
Expand All @@ -217,7 +199,6 @@ def extend(self, iter: Iterable) -> None:
>>> deque_collections_2.extend('cd')
>>> deque_collections_2
deque(['a', 'b', 'c', 'd'])

>>> list(our_deque_1) == list(deque_collections_1)
True
>>> list(our_deque_2) == list(deque_collections_2)
Expand All @@ -226,11 +207,10 @@ def extend(self, iter: Iterable) -> None:
for val in iter:
self.append(val)

def extendleft(self, iter: Iterable) -> None:
def extendleft(self, iter: Iterable[Any]) -> None:
"""
Appends every value of iter to the beginning of the deque.
Time complexity: O(n)

>>> our_deque_1 = Deque([1, 2, 3])
>>> our_deque_1.extendleft([0, -1])
>>> our_deque_1
Expand All @@ -239,7 +219,6 @@ def extendleft(self, iter: Iterable) -> None:
>>> our_deque_2.extendleft('ba')
>>> our_deque_2
['a', 'b', 'c', 'd']

>>> from collections import deque
>>> deque_collections_1 = deque([1, 2, 3])
>>> deque_collections_1.extendleft([0, -1])
Expand All @@ -249,7 +228,6 @@ def extendleft(self, iter: Iterable) -> None:
>>> deque_collections_2.extendleft('ba')
>>> deque_collections_2
deque(['a', 'b', 'c', 'd'])

>>> list(our_deque_1) == list(deque_collections_1)
True
>>> list(our_deque_2) == list(deque_collections_2)
Expand All @@ -262,24 +240,20 @@ def pop(self) -> Any:
"""
Removes the last element of the deque and returns it.
Time complexity: O(1)

@returns topop.val: the value of the node to pop.

>>> our_deque = Deque([1, 2, 3, 15182])
>>> our_popped = our_deque.pop()
>>> our_popped
15182
>>> our_deque
[1, 2, 3]

>>> from collections import deque
>>> deque_collections = deque([1, 2, 3, 15182])
>>> collections_popped = deque_collections.pop()
>>> collections_popped
15182
>>> deque_collections
deque([1, 2, 3])

>>> list(our_deque) == list(deque_collections)
True
>>> our_popped == collections_popped
Expand All @@ -302,24 +276,20 @@ def popleft(self) -> Any:
"""
Removes the first element of the deque and returns it.
Time complexity: O(1)

@returns topop.val: the value of the node to pop.

>>> our_deque = Deque([15182, 1, 2, 3])
>>> our_popped = our_deque.popleft()
>>> our_popped
15182
>>> our_deque
[1, 2, 3]

>>> from collections import deque
>>> deque_collections = deque([15182, 1, 2, 3])
>>> collections_popped = deque_collections.popleft()
>>> collections_popped
15182
>>> deque_collections
deque([1, 2, 3])

>>> list(our_deque) == list(deque_collections)
True
>>> our_popped == collections_popped
Expand All @@ -340,14 +310,12 @@ def is_empty(self) -> bool:
"""
Checks if the deque is empty.
Time complexity: O(1)

>>> our_deque = Deque([1, 2, 3])
>>> our_deque.is_empty()
False
>>> our_empty_deque = Deque()
>>> our_empty_deque.is_empty()
True

>>> from collections import deque
>>> empty_deque_collections = deque()
>>> list(our_empty_deque) == list(empty_deque_collections)
Expand All @@ -359,14 +327,12 @@ def __len__(self) -> int:
"""
Implements len() function. Returns the length of the deque.
Time complexity: O(1)

>>> our_deque = Deque([1, 2, 3])
>>> len(our_deque)
3
>>> our_empty_deque = Deque()
>>> len(our_empty_deque)
0

>>> from collections import deque
>>> deque_collections = deque([1, 2, 3])
>>> len(deque_collections)
Expand All @@ -379,19 +345,17 @@ def __len__(self) -> int:
"""
return self._len

def __eq__(self, other: "Deque") -> bool:
def __eq__(self, other: object) -> bool:
"""
Implements "==" operator. Returns if *self* is equal to *other*.
Time complexity: O(n)

>>> our_deque_1 = Deque([1, 2, 3])
>>> our_deque_2 = Deque([1, 2, 3])
>>> our_deque_1 == our_deque_2
True
>>> our_deque_3 = Deque([1, 2])
>>> our_deque_1 == our_deque_3
False

>>> from collections import deque
>>> deque_collections_1 = deque([1, 2, 3])
>>> deque_collections_2 = deque([1, 2, 3])
Expand All @@ -400,12 +364,15 @@ def __eq__(self, other: "Deque") -> bool:
>>> deque_collections_3 = deque([1, 2])
>>> deque_collections_1 == deque_collections_3
False

>>> (our_deque_1 == our_deque_2) == (deque_collections_1 == deque_collections_2)
True
>>> (our_deque_1 == our_deque_3) == (deque_collections_1 == deque_collections_3)
True
"""

if not isinstance(other, Deque):
return NotImplemented

me = self._front
oth = other._front

Expand All @@ -422,18 +389,16 @@ def __eq__(self, other: "Deque") -> bool:

return True

def __iter__(self) -> "_Iterator":
def __iter__(self) -> Deque._Iterator:
"""
Implements iteration.
Time complexity: O(1)

>>> our_deque = Deque([1, 2, 3])
>>> for v in our_deque:
... print(v)
1
2
3

>>> from collections import deque
>>> deque_collections = deque([1, 2, 3])
>>> for v in deque_collections:
Expand All @@ -449,7 +414,6 @@ def __repr__(self) -> str:
Implements representation of the deque.
Represents it as a list, with its values between '[' and ']'.
Time complexity: O(n)

>>> our_deque = Deque([1, 2, 3])
>>> our_deque
[1, 2, 3]
Expand Down