#### Max Sum Sliding Window

p
"""
Given an array of integer elements and an integer 'k', we are required to find the
maximum sum of 'k' consecutive elements in the array.

Instead of using a nested for loop, in a Brute force approach we will use a technique
called 'Window sliding technique' where the nested loops can be converted to a single
loop to reduce time complexity.
"""

from __future__ import annotations

def max_sum_in_array(array: list[int], k: int) -> int:
"""
Returns the maximum sum of k consecutive elements
>>> arr = [1, 4, 2, 10, 2, 3, 1, 0, 20]
>>> k = 4
>>> max_sum_in_array(arr, k)
24
>>> k = 10
>>> max_sum_in_array(arr,k)
Traceback (most recent call last):
...
ValueError: Invalid Input
>>> arr = [1, 4, 2, 10, 2, 13, 1, 0, 2]
>>> k = 4
>>> max_sum_in_array(arr, k)
27
"""
if len(array) < k or k < 0:
raise ValueError("Invalid Input")
max_sum = current_sum = sum(array[:k])
for i in range(len(array) - k):
current_sum = current_sum - array[i] + array[i + k]
max_sum = max(max_sum, current_sum)
return max_sum

if __name__ == "__main__":
from doctest import testmod
from random import randint

testmod()
array = [randint(-1000, 1000) for i in range(100)]
k = randint(0, 110)
print(f"The maximum sum of {k} consecutive elements is {max_sum_in_array(array,k)}")