Number of Sub-arrays of Size K and Average

lcpy gen -n 1343   # by problem number
lcpy gen -s number_of_sub_arrays_of_size_k_and_average_greater_than_or_equal_to_threshold   # by problem name

Input: arr = [2,2,2,2,5,5,5,8], k = 3, threshold = 4
Output: 3
Explanation: Sub-arrays [2,5,5],[5,5,5] and [5,5,8] have averages 4, 5 and 6 respectively. All other sub-arrays of size 3 have averages less than 4 (the threshold).

Input: arr = [11,13,17,23,29,31,7,5,2,3], k = 3, threshold = 5
Output: 6
Explanation: The first 6 sub-arrays of size 3 have averages greater than 5. Note that averages are not integers.

class Solution:
    def num_of_subarrays(self, arr: list[int], k: int, threshold: int) -> int:
        window = sum(arr[:k])
        target = k * threshold
        count = 1 if window >= target else 0
        for i in range(k, len(arr)):
            window += arr[i] - arr[i - k]
            if window >= target:
                count += 1
        return count