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44 changes: 44 additions & 0 deletions dynamic_programming/max_sub_array_sum.py
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from typing import List

def max_sub_array_sum(arr: List[int], size: int) -> int:
"""
Finds the maximum sum of a subarray within the given array using Kadane's algorithm.

Args:
arr (list): The input array of numbers.
size (int): The size of the array.

Returns:
int: The maximum sum of a subarray within the array.

Example:
>>> arr = [-2, -3, 4, -1, -2, 5, -3]
>>> maxSubArraySum(arr, len(arr))
6
In this example, the input array is [-2, -3, 4, -1, -2, 5, -3]. The maximum sum of a subarray
within this array is 6, which corresponds to the subarray [4, -1, -2, 5].

>>> arr = [-3, -4, 5, -1, 2, -4, 6, -1]
>>> maxSubArraySum(arr, len(arr))
8

References:
https://en.wikipedia.org/wiki/Maximum_subarray_problem
"""
max_till_now = arr[0]
max_ending = 0

for i in range(size):
max_ending = max_ending + arr[i]
if max_ending < 0:
max_ending = 0
elif max_till_now < max_ending:
max_till_now = max_ending

return max_till_now


if __name__ == "__main__":
import doctest

doctest.testmod()
38 changes: 38 additions & 0 deletions web_programming/sliding_window.py
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from typing import List

def sliding_window(elements: List[int], window_size: int) -> List[List[int]]:
"""
Generate sliding windows of a specified size over a list of elements.

Args:
elements (list): The input list of elements.
window_size (int): The size of the sliding window.

Returns:
list: A list of sliding windows.

Example:
>>> lst = [1, 2, 3, 4, 5, 6, 7, 8]
>>> result = sliding_window(lst, 3)
>>> print(result)
[[1, 2, 3], [2, 3, 4], [3, 4, 5], [4, 5, 6], [5, 6, 7], [6, 7, 8]]

References:
https://stackoverflow.com/questions/8269916/what-is-sliding-window-algorithm-examples
"""

if len(elements) <= window_size:
return [elements]

windows = []
for i in range(len(elements) - window_size + 1):
window = elements[i : i + window_size]
windows.append(window)

return windows


if __name__ == "__main__":
import doctest

doctest.testmod()
34 changes: 34 additions & 0 deletions web_programming/sliding_window_using_generators.py
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from typing import List

def sliding_window(elements: List[int], window_size: int) -> List[List[int]]:
"""
Generate sliding windows of size window_size from the given elements.

Args:
elements (list): The input list of elements.
window_size (int): The size of the sliding window.

Returns:
generator: A generator that yields sublists of size window_size.

Example:
>>> lst = [1, 2, 3, 4, 5, 6, 7, 8]
>>> sw_gen = sliding_window(lst, 3)
>>> print(next(sw_gen))
[1, 2, 3]
>>> print(next(sw_gen))
[2, 3, 4]

References:
https://stackoverflow.com/questions/8269916/what-is-sliding-window-algorithm-examples
"""
if len(elements) <= window_size:
return elements
for i in range(len(elements) - window_size + 1):
yield elements[i : i + window_size]


if __name__ == "__main__":
import doctest

doctest.testmod()