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[mypy] Fix type annotations in data_structures/stacks/next_greater_element.py (#5763)

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* Fix type annotations in next_greater_element.py

* Refactor next_greater_element.py
This commit is contained in:
Dylan Buchi 2021-11-05 16:45:37 -03:00 committed by GitHub
parent 1a43c92c77
commit e7381b513b
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1 changed files with 19 additions and 16 deletions
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35
data_structures/stacks/next_greater_element.py
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@ -1,8 +1,10 @@
from __future__ import annotations
arr = [-10, -5, 0, 5, 5.1, 11, 13, 21, 3, 4, -21, -10, -5, -1, 0] arr = [-10, -5, 0, 5, 5.1, 11, 13, 21, 3, 4, -21, -10, -5, -1, 0]
expect = [-5, 0, 5, 5.1, 11, 13, 21, -1, 4, -1, -10, -5, -1, 0, -1] expect = [-5, 0, 5, 5.1, 11, 13, 21, -1, 4, -1, -10, -5, -1, 0, -1]
def next_greatest_element_slow(arr: list) -> list: def next_greatest_element_slow(arr: list[float]) -> list[float]:
""" """
Get the Next Greatest Element (NGE) for all elements in a list. Get the Next Greatest Element (NGE) for all elements in a list.
Maximum element present after the current one which is also greater than the Maximum element present after the current one which is also greater than the
@ -10,10 +12,13 @@ def next_greatest_element_slow(arr: list) -> list:
>>> next_greatest_element_slow(arr) == expect >>> next_greatest_element_slow(arr) == expect
True True
""" """
result = [] result = []
for i in range(0, len(arr), 1): arr_size = len(arr)
next = -1
for j in range(i + 1, len(arr), 1): for i in range(arr_size):
next: float = -1
for j in range(i + 1, arr_size):
if arr[i] < arr[j]: if arr[i] < arr[j]:
next = arr[j] next = arr[j]
break break
@ -21,7 +26,7 @@ def next_greatest_element_slow(arr: list) -> list:
return result return result
def next_greatest_element_fast(arr: list) -> list: def next_greatest_element_fast(arr: list[float]) -> list[float]:
""" """
Like next_greatest_element_slow() but changes the loops to use Like next_greatest_element_slow() but changes the loops to use
enumerate() instead of range(len()) for the outer loop and enumerate() instead of range(len()) for the outer loop and
@ -31,7 +36,7 @@ def next_greatest_element_fast(arr: list) -> list:
""" """
result = [] result = []
for i, outer in enumerate(arr): for i, outer in enumerate(arr):
next = -1 next: float = -1
for inner in arr[i + 1 :]: for inner in arr[i + 1 :]:
if outer < inner: if outer < inner:
next = inner next = inner
@ -40,7 +45,7 @@ def next_greatest_element_fast(arr: list) -> list:
return result return result
def next_greatest_element(arr: list) -> list: def next_greatest_element(arr: list[float]) -> list[float]:
""" """
Get the Next Greatest Element (NGE) for all elements in a list. Get the Next Greatest Element (NGE) for all elements in a list.
Maximum element present after the current one which is also greater than the Maximum element present after the current one which is also greater than the
@ -53,21 +58,19 @@ def next_greatest_element(arr: list) -> list:
>>> next_greatest_element(arr) == expect >>> next_greatest_element(arr) == expect
True True
""" """
stack = [] arr_size = len(arr)
result = [-1] * len(arr) stack: list[float] = []
result: list[float] = [-1] * arr_size
for index in reversed(range(len(arr))): for index in reversed(range(arr_size)):
if len(stack): if stack:
while stack[-1] <= arr[index]: while stack[-1] <= arr[index]:
stack.pop() stack.pop()
if len(stack) == 0: if not stack:
break break
if stack:
if len(stack) != 0:
result[index] = stack[-1] result[index] = stack[-1]
stack.append(arr[index]) stack.append(arr[index])
return result return result